Methods and apparatus for using location information to manage spillover in an audience monitoring system

ABSTRACT

Methods, apparatus, and articles of manufacture for using location information to manage spillover in an audience monitoring system are disclosed. In an example method, a first location signal and a second location signal are received substantially simultaneously at a portable metering device. The first location signal is emitted via a first device located at a first location and includes a first signal characteristic associated with the first location. The second location signal is emitted via a second device located at a second location and includes a second signal characteristic associated with the second location. The first location signal or the second location signal is selected based on the first and second signal characteristics. Media monitoring information is generated based on the selected signal.

RELATED APPLICATIONS

This patent is a continuation of U.S. patent application Ser. No.11/692,087, filed Mar. 27, 2007, which is a continuation ofInternational Patent Application Serial No. PCT/US2005/034743, filedSep. 27, 2005, which claims the benefit of U.S. Provisional ApplicationSer. No. 60/613,646, filed on Sep. 27, 2004, U.S. ProvisionalApplication Ser. No. 60/614,939, filed on Sep. 29, 2004, and U.S.Provisional Application Ser. No. 60/670,936, filed on Apr. 13, 2005, allof which are hereby incorporated herein by reference in theirentireties.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to media monitoring and, moreparticularly, to methods and apparatus for using audience memberlocation information to monitor media consumption.

BACKGROUND

Consuming media presentations generally involves listening to audioinformation and/or viewing video information such as, for example, radioprograms, music, television programs, movies, still images, etc.Media-centric companies such as, for example, advertising companies,broadcasting networks, etc. are often interested in the viewing andlistening interests of their audience to better market their products. Awell-known technique often used to measure the exposure and/or number ofaudience members exposed to media involves awarding media exposurecredit to a media presentation each time an audience member is exposedto the media presentation.

The awarding of media exposure credit is often determined by monitoringthe media consumption of audience members. The media consumptionactivities of audience members are often monitored using personalportable metering devices (PPMs), which are also known as portablemetering devices and portable personal meters. A PPM is an electronicdevice that is typically worn (e.g., clipped to a belt or other apparel)or carried by an audience member. In general, PPMs are configured to usea variety of techniques to monitor the media consumption (e.g., viewingand/or listening activities) of a person. For example, one technique formonitoring media consumption involves detecting or collectinginformation (e.g., ancillary codes, signatures, etc.) from audio and/orvideo signals that are emitted or presented by media delivery devices(e.g., televisions, stereos, speakers, computers, etc.)

While wearing a PPM, an audience member or monitored individual performstheir usual daily routine, which may include listening to the radioand/or other sources of audio media and/or watching television programsand/or other sources of visual media. As the audience member consumes(e.g., views, listens to, etc.) media, a PPM associated with (e.g.,assigned to and carried by) that audience member may detect audio and/orvideo information associated with the media and generate monitoringdata. In general, monitoring data may include any information that isrepresentative of (or associated with) and/or that may be used toidentify a particular media presentation (e.g., a song, a televisionprogram, a movie, a video game, etc.) For example, the monitoring datamay include signatures that are collected or generated by the PPM basedon the media, audio codes that are broadcast simultaneously with (e.g.,embedded in) the media, etc.

As a person wearing a PPM travels throughout their household, the PPMreceives audio and/or video content information provided by mediadelivery devices (e.g., televisions, radios, etc.) distributedthroughout the household. The audio/video content may be encoded tofacilitate subsequent identification of the audio/video content and/orthe PPMs may be configured to use signature generation techniques toidentify audio/video content received by the PPMs. In any case, eachperson's PPM may receive different audio/video content based on theperson's unique location (e.g., within their household, at anotherlocation outside their household, etc.) and their location relative tothe one or more media delivery devices to which they and their PPM areexposed.

Unfortunately, the typical household presents unique monitoringchallenges to the PPM. For example, a typical household includesmultiple media delivery devices, each configured to deliver mediacontent to specific viewing and/or listening areas located within thehome. A PPM, carried by a person who is located in one of the viewingand/or listening areas, is configured to detect any media content beingdelivered in the viewing and/or listening area and to credit theprogramming associated with the media content as having been consumed.Thus, the PPM operates on the premise that any media content detected bythe PPM is associated with programming that was consumed by the personcarrying the PPM. However, in some cases, a person's PPM may detectmedia content that is emitted by a media delivery device that is notlocated within the viewing or listening proximity of the person carryingthe PPM thereby causing the detected programming to be improperlycredited. The ability of the PPM to detect audio/video content beingdelivered outside of the viewing and/or listening proximity of theperson carrying the PPM is an effect referred to as “spillover” becausethe media content being delivered outside of the viewing and/orlistening proximity of the person carrying the PPM is described as“spilling over” into the area occupied by the person carrying the PPM.Spillover may occur, for example, in a case where a monitored individualin a bedroom is reading a book, but their PPM detects audio/videocontent delivered by a television in an adjacent living room, i.e.,outside of their viewing/listening proximity, causing the audio/videocontent to be improperly credited as having been consumed.

Another effect, referred to as “hijacking” occurs when a person's PPMdetects audio/video content being emitted from multiple media deliverydevices at the same time. For example, an adult watching a televisionnews program in a household kitchen may be located near a householdfamily room in which children are watching a television cartoon programon a different television. Yet, the cartoon programming delivered by thefamily room television may, in some cases, have signals that overpoweror “hijack” the signals associated with the news programming beingemitted by the kitchen television. As a result, the adult's PPM mayinaccurately credit the cartoon program as having been viewed by theadult and fail to credit the news program with any viewing. Stillfurther, other common difficulties such as varying volume levels,varying audio/video content type (e.g., sparse, medium, rich, etc.),varying household transmission characteristics due to open/closed doors,movement and/or placement of furniture, acoustic characteristics of roomlayouts, wall construction, floor coverings, ceiling heights, etc. oftenlead to inaccurate audio/video content consumption detection by PPMs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates an example area in which audience member locationinformation may be collected and used to monitor media consumption.

FIG. 1B illustrates location analysis indicia overlaid onto the examplehousehold of FIG. 1A.

FIG. 1C illustrates an example location detection diagram overlaid ontothe example household of FIG. 1A.

FIG. 2 is a block diagram of the example personal portable meteringdevice of FIG. 1A.

FIG. 3 is a block diagram of one of the example base units of FIG. 1A.

FIGS. 4 and 5 depict example placement square grids overlaid ontoexample plan views of two different representative households in whichthe methods, apparatus and articles of manufacture described herein maybe implemented.

FIGS. 6 and 7 depict example placement radial grids overlaid onto thehouseholds of FIGS. 3 and 4.

FIGS. 8 and 9 depict media center-centric layouts in which bounded areasare used to illustrate the areas in which media content presented byeach media delivery center may be detected by a PPM.

FIG. 10 depicts a detailed view of an example bounded area that may beused to implement the bounded areas of FIGS. 8 and 9.

FIG. 11A is a flow diagram of an example method that may be used tocollect time-stamped location information associated with the locationof a PPM.

FIG. 11B is a flow diagram of an example method that may be used tocollect time-stamped media monitoring information associated with mediadetected by the PPM.

FIG. 11C is a flow diagram of an example method that may be used toanalyze the time-stamped location information and the time-stamped mediamonitoring information collected in connection with the example methodsof FIGS. 11A and 11B.

FIG. 12A is a flow diagram of an example method that may be used todetermine when a PPM is in a room or space that does not include anymedia delivery centers.

FIG. 12B is a flow diagram of an example method that may be used togenerate media monitoring information based on the location of a PPM.

FIG. 13A is a flow diagram of an example method that may be used tooutput interference media codes.

FIG. 13B is a flow diagram of an example method that may be used todetermine the location of a PPM within a room.

FIGS. 14A-14E are flow diagrams of example methods that may be used toenhance the accuracy of the location information detected using the PPM104.

FIG. 15 is a flow diagram of another example method that may be used tomanage spillover.

FIG. 16 is a flow diagram of another example method that may be used tomanage spillover.

FIG. 17 is a block diagram of an example processor system that may beused to implement some or all of the example methods and apparatusdescribed herein.

FIG. 18 is another example location monitoring system that may be usedto implement the methods and apparatus described herein.

FIGS. 19-21 are example sensor placement configurations that may be usedto place the sensor units of FIG. 18 throughout a household.

FIG. 22 is a floor plan view of an example household illustrating anexample placement configuration for the sensor units of FIG. 18.

FIG. 23 is an example method that may be used to collect, manage andanalyze media monitoring information and location information associatedwith media consumption activities of an audience member using theexample location monitoring system of FIG. 18.

FIG. 24 is an example method that may be implemented in combination withthe example method of FIG. 23 and used to generate location informationvia the example monitoring system of FIG. 18.

FIGS. 25A-25B illustrate an example method that may be implemented incombination with the example method of FIG. 23 and used to analyzelocation and media monitoring information via a central processingsystem.

DETAILED DESCRIPTION

Although the following discloses example systems including, among othercomponents, software executed on hardware, it should be noted that suchsystems are merely illustrative and should not be considered aslimiting. For example, it is contemplated that any or all of thesehardware and software components could be embodied exclusively inhardware, exclusively in software, or in any combination of hardware andsoftware. Accordingly, while the following describes example systems,persons having ordinary skill in the art will readily appreciate thatthe examples provided are not the only way to implement such systems.

In general, the example methods and apparatus described herein may beused to manage signal spillover and/or other sources of media monitoringinaccuracies in the course of an audience member's exposure to mediasources or media presentations to more accurately assess the consumptionof those media sources or presentations. As described in greater detailbelow, example methods and apparatus may be used to prevent signalspillover from adversely affecting results of media monitoring. Ingeneral, some of the example methods and apparatus for managing (e.g.,preventing) signal spillover include using location detectiontechnologies, placing media code interference apparatus throughoutspaces and/or rooms in which media delivery devices are not placed, andusing heuristic-based algorithms to more accurately determine thelocation of audience members and/or the locations of the mediapresentation devices via which media is consumed.

Although some of the example systems and methods are described below asmonitoring media consumption by using location information to detectspillover in an audience monitoring system. The example systems andmethods may also be implemented as described below to use locationinformation to detect the location of a person in a home and to betterunderstand media consumption habits of audience members. In some exampleimplementations, the example methods and systems described below may uselocation information to determine the location of an audience memberwithin a particular room or space of a household and to determinewhether the audience member is sufficiently exposed to mediapresentations (e.g., radio programs, television programs, movies,computer information, etc.). An example implementation involvescollecting location information associated with the location of anaudience member to determine if the audience member is actively oreffectively consuming a proximate or otherwise consumable media source.For example, if an audience member is within a room, space, or locationthat has a readily visible or audible media delivery device, theaudience member is likely consuming any media presented by the mediadelivery device.

Although some example implementations may be used to determine that aperson is generally located within a room or area of a household, otherexample implementations may be used to determine relatively more preciselocations of a person within a particular room using, for example, X-Ylocation coordinates corresponding to a particular room or a particularhousehold. Relatively more precise location coordinates provide an evenbetter understanding of audience members' viewing habits. For example,although an audience member is located within a room having a televisionthat is presenting or delivering a television program, the relativelymore precise location information may indicate that the audience memberis not facing the television, but is instead, for example, working on acomputer and is not sufficiently exposed to the television to consumethe television media. Of course, the example systems and methodsdescribed herein may use location information in any number of otherways to generate media monitoring information to better understand theviewing habits of consumers.

The example methods and apparatus described herein may be implementedusing, for example, a PPM worn or carried by an audience member,location information systems (e.g., the global positioning system (GPS),radio frequency towers for triangulation, etc.), media code emitters,and media delivery devices, all of which may be used to collect andanalyze audience member location information and/or media monitoringinformation. In this manner, media presentations (e.g., audio, video,still images, Internet information, computer information, etc.) may begiven appropriate media exposure credit.

For purposes of clarity, the example methods and apparatus are describedherein with respect to an example geographic area 100 shown in FIG. 1A.Although, the example geographic area 100 is shown by way of example asindoor and outdoor areas associated with a household 102, the examplemethods and apparatus described herein may be used in any other area(s)or environment(s).

Location information is generally collected to determine rooms orlocations of the household 102 within which an audience member islocated while consuming or being exposed to media information. Locationinformation may include, for example, a plurality of geographic, global,or position coordinates that may be used to analyze the movements of aperson or an audience member from one location to another. As describedin greater detail below, location information may be collected,obtained, generated, etc. using any suitable location detection devices,location detection systems, and/or location detection techniques.Specifically, the location detection devices described below may be wornor otherwise carried by a person or audience member.

Location information may be continuously collected in indoorenvironments and/or outdoor environments via, for example, an examplePPM 104 that may be carried or worn by an audience member 106 as shownin FIG. 1A. In particular, the example PPM 104 may be configured tomonitor the audience member 106 via one or more location detectiondevices and/or motion detection devices described below in connectionwith FIG. 2. The location detection devices and motion detection devicesmay be configured to enable the example PPM 104 to collect audiencemember location information and/or motion information in indoorenvironments and/or outdoor environments. In this manner, when anaudience member moves among indoor areas and outdoor areas asubstantially continuous location history may be tracked or logged foreach audience member to develop movement information.

Media monitoring information may include any information associated withmedia that is consumed (e.g., viewed, listened to, interacted with,etc.) by an audience member. Media presentations may include, forexample, television programming, radio programming, movies, songs,advertisements, Internet information, and/or any other videoinformation, audio information, still image information, and computerinformation to which a person may be exposed. Media monitoringinformation may be generated based on, for example, audio codes,signatures, radio frequency (RF) codes, and/or any other codes,information, or identifiers that may be extracted from or otherwiseassociated with a media presentation to which an audience member isexposed. As described in greater detail below, media monitoringinformation may be collected generated, obtained, etc. using anysuitable media consumption detection device and/or any suitable mediaconsumption detection technique.

In one implementation, the PPM 104 may tag media monitoring informationwith respective media location information to generatemovement-annotated media monitoring information. In other words, in asubstantially real-time process, the PPM 104 may substantiallycontinuously combine time-stamped media monitoring information withtime-stamped location information that corresponds to the locations atwhich the PPM 104 collected the time-stamped media monitoringinformation. In this manner, subsequent analyses can be used todetermine the locations at which the audience member 106 was exposed toparticular media. Alternatively, time-stamped media monitoringinformation may be combined with time-stamped location information in apost process. For example, time-stamped media monitoring information andtime stamped location information may be stored within a memory (e.g.,the memory 204 of FIG. 2) of the PPM 104 or may be stored in a storagedevice that is separate from the storage device (e.g., anotherinformation processing system) and may then be combined, joined, orotherwise interrelated in a subsequent process to generatelocation-annotated media monitoring information. Other information withwhich the collected information may be annotated includes, for example,audience identification information and PPM identification information.

Traditional methods for measuring media consumption typically track orlog the media presentations to which an audience member is exposed andaward a media exposure credit to a media source or presentation any timean audience member is in the vicinity of that media presentation or,more generally, within a distance of the media delivery device fromwhich it is likely the audience member is consuming the media or fromwhich it is likely a PPM will detect a media code associated with themedia presentation. However, these traditional methods may produceinconsistent or inaccurate results due to spillover that occurs when theaudience member 106 is in the vicinity of a media presentation, but isnot adequately exposed to the media presentation. For example, withinthe household 102, spillover may occur when the audience member 106 islocated within a room having no media delivery device, but the PPM 104detects media codes emanating from a media delivery device in anotherroom. Logging the media codes that have spilled over from a space thatis outside of the listening/viewing proximity of the audience member 106results in an inaccurate representation of the media programs consumedby the audience member 106.

As shown in FIG. 1A, the household 102 and the audience member 106wearing the PPM 104 are located within the example geographic area 100.As described below, the PPM 104 may be used to collect locationinformation, motion information, and media monitoring information withinthe household 102, outside of the household 102, and within structuresother than the household 102.

The PPM 104 may be configured to substantially continuously generate,obtain, and/or collect media monitoring information, locationinformation, and motion information. As described in greater detailbelow in connection with FIG. 2, the PPM 104 may include one or moremedia detection devices used to detect presented media and generate orcollect media monitoring information or media-related data based on, forexample, audio signals, visual signals, radio frequency signals, etc. Inaddition, the PPM 104 may include one or more location or positioningdevices that enable the PPM 104 to collect location or positioninformation from one or more location information systems and/or to sendlocation information to one or more location information systems. Theexample geographic area 100 includes one or more location informationsystems that may be used to communicate location information to/from thePPM 104.

The location information systems may be implemented using, for example,one or more radio frequency (RF) transceiver towers represented in FIG.1A by a RF transceiver tower 108 and/or one or more satellitesrepresented in FIG. 1A by a satellite 110. In addition, the interiorenvironment of the household 102 may include one or more locationinformation systems described below.

The PPM 104 may collect media monitoring information (e.g., ancillarycodes, signatures, etc.) associated with any media (e.g., video, audio,movies, music, still pictures, advertising, computer information, etc.)to which the audience member 106 is exposed. For example, the PPM 104may be configured to obtain audio codes, generate or collect signatures,etc. that may be used to identify video programs (e.g., DVD movies,television programming, etc.), audio programs (e.g., CD audio, radioprogramming, etc.), etc. In particular, the household 102 includes aplurality of media delivery centers 112, each of which may include oneor more media delivery devices such as, for example, a television, aradio, etc. as well as one or more media playback devices such as, forexample, a DVD player, VCR, etc. Using one or more media detectiondevices described below in connection with FIG. 2, the PPM 104 maycollect media monitoring information associated with media presented ordelivered by one or more of the media delivery centers 112 and to whichthe audience member 106 may be exposed.

Location information collected by the PPM 104 may be used to generatemovement information and/or to analyze the movements of the audiencemember 106. For example, movement information may be stored as aplurality of location coordinates or location information that may beconverted to movement information during subsequent processing bygenerating movement paths that indicate or track the movements of anaudience member. The PPM 104 may also include motion detection devicesas described below in connection with FIG. 2. Motion detection devicesmay be used in combination with location detection devices to moreaccurately determine the locations of the audience member 106. Forexample, the motion detection devices may provide motion informationsuch as, for example, acceleration, direction of travel, etc., which maybe used to supplement location information and more accurately determinethe locations of the audience member 106.

The RF transceiver tower 108 may be used in combination with any RFcommunication technology such as, for example, a cellular communicationtechnology (e.g., GSM, CDMA, TDMA, AMPS, etc.) In one exampleconfiguration, the RF transceiver tower 108 may be configured totransmit or broadcast position information and/or any type of signalthat may be used by the PPM 104 to generate location information. Forexample, the RF transceiver tower 108 may transmit information havinggeographic location information and time codes. More specifically, theRF transceiver tower 108 may be associated with a particular or uniqueset of geographic location coordinates (i.e., geographic locationinformation), that define or indicate the location of the RF transceivertower 108 within a global positioning grid. The time codes may beassociated with a time at which a particular signal is transmitted bythe RF transceiver tower 108.

The geographic location information and the time codes received from aplurality of RF transceiver towers may be used by the PPM 104 to performtriangulation processes to determine the location(s) of the PPM 104.Triangulation processes are well known in the art and, thus, are notdescribed further herein. Although the RF transceiver tower 108 isdepicted as being located in an outdoor environment, the PPM 104 mayinclude location technologies that communicate with the RF transceivertower 108 when the PPM 104 is located within indoor environments (e.g.,within the household 102) or outdoor environments.

The satellite 110 may also be used to communicate location informationto/from the PPM 104. For example, the satellite 110 may be used toimplement any satellite positioning system (SPS) such as, for example,the global positioning system (GPS) that continuously broadcastsposition-related information. In this manner, the PPM 104 may receivethe position-related information from the satellite 110 to determine thelocation(s) and movement of the PPM 104.

One or more location information systems may also be located within thehousehold 102. As shown in FIG. 1A, an example location informationsystem includes a plurality of base units 114. The base units 114 mayinclude one or more location detection technologies, some of which aredescribed below in connection with FIG. 3. The base units 114 may beconfigured to work cooperatively with the PPM 104 to substantiallycontinuously generate location information associated with the locationof the PPM 104 as the audience member 106 moves among various areaswithin or around the household 102. While the location detectiontechnologies and capabilities are described as being integrated withinthe base units 114, such technologies and capabilities could instead beincorporated within other devices or systems separate from the baseunits 114.

The base units 114 may also be configured to detect media codes and/ordeliver or emit media codes. For example, the base units 114 may becommunicatively coupled to the media delivery centers 112 via audioand/or video communication paths and configured to obtain audio and/orvideo codes associated with media presentations delivered by the mediadelivery centers 112. In this manner, the base units 114 may logtime-stamped media monitoring information that indicates the media towhich the audience member 106 may be exposed. As described in greaterdetail below in connection with example methods of FIGS. 11A-11C, thetime-stamped media monitoring information may be compared and/orcombined with time-stamped location information collected by the PPM 104to determine the locations of the audience member 106 and the mediapresentations to which the audience member 106 was exposed.

The base units 114 may also generate media codes via media codegenerators as described in greater detail below in connection with FIG.3. The media code generators may be used to generate interference ordisruptor media codes in areas proximate to base units 114 locatedwithin rooms or areas (e.g., hallways) having no media delivery centers.For example, a room 115 a of the household 102 has no media deliverycenters while rooms 115 b and 115 c each includes the media deliverycenters 112. The base unit 114 located in the room 115 a may beconfigured to emit an interference media code that substantiallydisrupts or blocks media codes from the media delivery centers 112 thatcould otherwise spillover into the room 115 a. In this manner, when thePPM 104 is in the room 115 a, any media codes that spillover from therooms 115 b and 115 c are overpowered, disrupted, blocked or otherwiseobfuscated by the interference media codes broadcast by the base unit114 in the room 115 a so that the PPM 104 only detects the interferencemedia codes.

The interference media codes may be blank values or key values that,during subsequent analyses of the information, are used to discard ordisregard information collected within rooms (e.g., the room 115 a) orspaces (e.g., hallways) having no media delivery devices. The base unit114 may emit the interference codes at various frequencies. For example,the frequencies at which the base units 114 emit interference codes maybe selected to ensure that media codes that spill over from other roomsare disrupted (i.e., not detectable to a PPM located in the same room asthe code disruptor) but allow the media codes of the room within whichthe PPM 104 is located to be detected by the PPM 104. Alternatively, thebase unit 114 may emit interference media codes at all of thefrequencies at which the television/media audio codes of other rooms orspaces are transmitted. Additionally, the base unit 114 may include amicrophone for sensing ambient noise/sound and may increase the strengthat which the interference media codes are emitted when the ambient noisein the room increases. Thus, the interference media codes would havelimited impact on (e.g., would not be perceptible by) people locatedwithin the vicinity of the base units 114.

In an alternative or additional implementation, the base units 114located in rooms or spaces having none of the media delivery centers 112may be configured to emit a white noise or other type of interfering ormasking noise or signal to prevent the PPM 104 from detecting any mediacodes that would otherwise spill over into the room or space having noneof the media delivery centers 112. The white noise or other type ofinterfering or masking noise may be delivered at a power level,strength, or volume that the human brain can tune out or easilydisregard without causing annoyance (or at least minimizing the level ofannoyance caused) to humans.

The base units 114 may be implemented using consoles that are placedanywhere within the rooms or spaces of a household. Alternatively oradditionally, the base units 114 may be implemented as wall-mountabledevices that can, for example, be plugged directly into an alternatingcurrent (AC) electrical outlet.

For cases in which the base units 114 are installed or placed only inrooms or spaces having media delivery centers (e.g., the media deliverycenters 112), the base units 114 may be configured to emit locationinformation associated only with their respective rooms. In this case,transmission fields of each of the base units 114 may be shaped using ashielding material to prevent, eliminate, or reduce spillover of thelocation information into adjacent rooms. For example, shieldingmaterials may be operatively coupled to the base units 114 to shape RFemission fields to prevent the base units 114 from spilling RFinformation into adjacent rooms or spaces by positioning the shieldingmaterial to block the transmission of signals toward any walls shared byadjacent rooms. For example, the shielding material may be applied tothe base units 114 to direct the emitted RF energy in a direction towardthe center of the room or space corresponding to the base unit 114. Themetal shield may also be positioned to block the transmission of signalstoward any walls shared by adjacent rooms. Using such a shield, alocation code signal propagates away from the walls shared by adjacentrooms so that spillover of the location codes into the adjacent room islimited or substantially eliminated. Although the location codes and/orother information emitted by the base units 114 may reflect off of oneor more surfaces in the room, the reflected signal would besubstantially weakened to significantly degrade or minimize the abilityof the reflected signal to travel through the wall. In this manner, ifthe PPM 104 detects audio codes and the location codes, then thecorresponding programming is associated with actual viewing. If insteadthe audio codes are detected but the location codes are not detected,then the detected audio codes may be disregarded as being caused byspillover.

Example movement information is shown in FIG. 1A as a first movementpath 116 a, a second movement path 116 b, and a third movement path 116c. The first movement path 116 a indicates that the audience member 106moved from one room to another. The second movement path 116 b indicatesthat the audience member 106 moved from a couch 117 to the mediadelivery center 112 and back. The third movement path 116 c indicatesthat the audience member 106 moved from the inside of the household 102to a location outside of the household 102. The example movement paths116 a-c may be generated using location information collected by the PPM104 in combination with any one or more suitable location informationsystems (e.g., the RF transceiver tower 108, the satellite 110, the baseunits 114, etc.). For example, the location information used to generatethe movement paths 116 a and 116 b may be generated using informationreceived from the RF transceiver towers 108, the base units 114, or acombination thereof.

The location information used to generate the movement path 116 c mayinclude location information generated using location informationsystems that function for indoor use and/or outdoor use. One suchlocation information system may be, for example, the RF transceivertower 108. Alternatively, location information associated with themovement path 116 c may be generated using a combination of locationinformation systems such as, for example, a first location informationsystem that functions primarily or only in indoor environments and asecond location information system that functions primarily or only inoutdoor environments. In that case, the first location informationsystem for indoor use may be, for example, the base units 114 and thesecond location information system may be, for example, the satellite110. Using two location information systems (e.g., the base units 114and the satellite 110) in combination may require a handoff process toensure that the PPM 104 transitions substantially seamlessly fromworking with one location information system to working with another. Anexample handoff process may include a software routine that continuouslysearches for the signals from both location information systems andworks with the location information system providing the strongestsignal. Other software and/or circuitry may provide hysteresis to enableminimum/maximum threshold levels of signal strength to be used toprevent the PPM 104 from continuously switching between locationinformation systems.

The household 102 may also include a plurality of room differentiators118 a and 118 b. The room differentiators 118 a and 118 b may be placedin rooms and/or areas within rooms or spaces that are prone tospillover. For example, the room differentiators 118 a and 118 b may beplaced on or adjacent to opposing surfaces of a wall (e.g., a wall 119)separating two rooms or spaces. Each of the room differentiators 118 aand 118 b is configured to emit a code (e.g., an ancillary locationcode) or a signal at a particular frequency uniquely associated with arespective room. The room differentiators 118 a and 118 b may include ashort range signal broadcasting or signal emitting technology that iseasily attenuated by walls. In this manner, if the audience member 106is close to the wall 119 and the PPM 104 detects media codes from twodifferent media delivery centers 112, the short range codes emitted bythe room differentiators may be used by the PPM 104 to determine inwhich room the PPM 104 is located and, thus, to which media deliverycenter 112 the audience member 106 is exposed. The PPM 104 will onlydetect the short range code from the room differentiator located withinthe same room as the audience member 106 because the short range codesare configured to be substantially attenuated by walls. One suchtechnology that can be tuned to be easily attenuated by walls includesultrasound emitters. In such a configuration, the PPM 104 will includean ultrasound receiver. Of course, any other suitable technology couldbe used instead. For example, the room differentiators 118 a and 118 bcould be implemented using 802.11 emitters that are set to a low enoughsignal strength to be substantially attenuated by the wall 119.

In an example implementation in which the room differentiators 118 a and118 b are implemented using 802.11 emitters, each of the roomdifferentiators 118 a and 118 b may be configured to emit signals at alow power (i.e., weak signals), at a different frequency, and/or havingdifferent location codes. The differentiators 118 a and 118 b may beplaced near or on the wall 119 in each room such that the audiencemember 106 carrying the PPM 104 in the room 115 c will be closer to thedifferentiator 118 b because the differentiator 118 b is located in thesame room (e.g., the room 115 c) in which the PPM 104 is located. If thePPM 104 detects signals from both of the differentiators 118 a and 118 bat substantially the same time, then the stronger signal is used toidentify the one of the differentiators 118 a and 118 b that is in thesame room as the PPM 104. In this manner, the PPM 104 may log the roomwithin which it is located and use this information in combination withlocation information and media monitoring information to determine amedia presentation consumed by the audience member 106.

The information received from one of the differentiators 118 a and 118 bthat is within the same room as the PPM 104 may be logged by the PPM 104and used during subsequent analyses to determine the room in which thePPM 104 was collecting audio codes from media programs. If it isdetermined during subsequent analyses that the room within which the PPM104 is located contains a television or other media delivery device(e.g., the media delivery centers 112), any audio codes detected by thePPM 104 are associated with actual viewing. On the other hand, if theidentified room does not contain a television or other media deliverydevice, then any audio codes detected by the PPM 104 are identified asspillover codes and are disregarded.

The room differentiators 118 a and 118 b may be implemented using awall-mountable device that plugs directly into AC electrical outlets.Alternatively, the room differentiators 118 a and 118 b may beimplemented using a console mounted to a wall or stored on the floor. Abroadcasting transducer (e.g., a speaker) may be operatively coupled toand mounted within each of the room differentiators 118 a and 118 b.Alternatively, one or more broadcasting transducers may be tethered toeach of the room differentiators 118 a and 118 b and distributed evenlyalong opposing sides of a wall (e.g., the wall 119).

A home processing system 120 may be configured to communicate with thePPM 104 and/or the base units 114. In particular, the home processingsystem 120 may be communicatively coupled to one or more dockingstations (not shown) configured to receive the PPM 104 andcommunicatively couple the PPM 104 to the home processing system 120.The audience member 106 may periodically (e.g., nightly) place the PPM104 into a docking station to enable the home processing system 120 toobtain collected media monitoring information, location information,motion information, and/or any other information stored in the PPM 104.Alternatively, the PPM 104 may be communicatively coupled with the baseunits 114 via wireless and/or hardwired communications and mayperiodically communicate collected information to the home processingsystem 120 via one or more of the base units 114.

The home processing system 120 is communicatively coupled to a centralfacility 122 via a network 124. The central facility 122 is remotelylocated from the household 102 and is communicatively coupled to thehousehold 102 and other monitored sites (e.g., other households) via thenetwork 124. The central facility 122 obtains media consumption data,media monitoring data, location information, motion information, and/orany other monitoring data that is collected by various media monitoringdevices such as, for example, the PPM 104. The central facility 122includes a server 126 (i.e., a central processor system) and a database128 that may be implemented using any suitable memory and/or datastorage apparatus and techniques. The server 126 may be implementedusing, for example, a processor system similar or identical to theexample processor system 1710 depicted in FIG. 17. The server 126 may beconfigured to store information collected from the PPM 104 in thedatabase 128 and analyze the information. In addition, the server 126may be configured to generate calibration information for the PPM 104and/or other PPMs based on audio information or audio samples collectedduring an acoustic characterization process or calibration processperformed within the household 102.

The network 124 may be used to communicate information between thecentral facility 122 and devices or apparatus in the monitored household102. For example, the network 124 may be communicatively coupled to thebase units 114, the PPM 104, and/or the home processing system 120. Thenetwork 124 may be implemented using any suitable communicationinterface including, for example, telephone lines, a cable system, asatellite system, a cellular communication system, AC power lines, etc.

FIG. 1B illustrates location analysis indicia overlaid onto the examplehousehold 102 of FIG. 1A. The household 102 includes the plurality ofrooms 115 a-115 c separated by walls 119 and 154. Each of the rooms 115a-115 c is mapped using XY coordinates 156 of an XY grid 158. The XYcoordinates 156 are arranged to indicate general locations at which theaudience member 106 may reside when moving within the household 102. Asdescribed in greater detail below in connection with the example methodsof FIGS. 14A-14E, the XY coordinates 156 may be used to determine if thePPM 104 has collected accurate location information.

Additionally, a plurality of boundary zones 160 a, 160 b, and 160 c areeach overlaid onto the rooms 115 a-115 c, respectively. The boundaryzones 160 a-160 c indicate areas within the rooms 115 a-115 c that maybe defined by areas within a predefined distance from every wall of therooms 115 a-115 c. The boundary zones 160 a-160 c indicate areas withinwhich location information collected by the PPM 104 may be erroneouslyinterpreted as being associated with a room different than that withinwhich the PPM 104 is located. Specifically, the boundary zones 160 a-160c may be defined according to accuracy limitations of the PPM 104 and/orany of the location information systems (e.g., the RF tower 108, thesatellite 110, and the base units 114 of FIG. 1A). For example, if thePPM 104 is capable of collecting and/or generating location informationthat is accurate to within two feet, the boundary zones 160 a-160 c maybe predefined as extending two feet from each wall. As described ingreater detail below in connection with the example method of FIG. 14E,the boundary zones 160 a-160 c may be used to determine when locationinformation collected by the PPM 104 is likely to give inaccurateresults by indicating that the PPM 104 is in a room different from theone within which it is actually located.

Path lines 162 and 164 illustrate lines that extend betweencorresponding sequentially collected location coordinates (e.g., (X_(n),Y_(n)) and (X_(n+1), Y_(n+1))). As shown, the path line 162 isintersected by wall 119 and path line 164 indicates a path through adoorway 166. As described in greater detail below in connection with theexample methods of FIGS. 14A-14E, the path lines 162 and 164 may be usedto determine if the audience member 106 moved from one room (e.g., theroom 115 c) to another (e.g., the room 115 a).

Path line 168 illustrates a path extending between two sequentiallycollected location coordinates (e.g., (X_(n), Y_(n)) and (X_(n+1),Y_(n+1))). As described in greater detail below in connection with theexample method of FIG. 14C, a rate of travel associated with the pathline 168 may be used to determine if the audience member 106 could havepossibly moved from a first room (e.g., the room 115 b) to a second room(e.g., the room 115 c) via a doorway 170 in the wall 119.

FIG. 1C illustrates an example location detection system 172 in theexample household 102 of FIG. 1A. The example location detection system172 may be used to implement a location detection technique that issubstantially similar to a triangulation-based location detectiontechnique. The location detection system 172 may include two (or more)audio chirp transmitters (e.g., two of the base units 114) disposed atvarious locations in, for example, a single room (e.g., the room 115 b)of the household 102. The position of each audio chirp transmitter isknown and the audio chirp emitted by each of the transmitters may beused to uniquely identify the transmitter from which the audio chirporiginated. Referring to FIG. 1C, the PPM 104 may be configured toreceive audio chirps emitted from the base units 114 disposed within thesame room 115 b and determine its location within the room 115 b using alocation detection algorithm and the audio chirps. An example methodthat may be used to perform this location detection technique isdescribed in greater detail below in connection with FIG. 13B.

As shown in FIG. 1C, two base units 114 are disposed within the room 115b. Each of the base units 114 may be configured to emit a uniquelyidentifiable audio chirp that is detectable by the PPM 104. For example,each of the base units 114 may emit an audio chirp at a unique frequencyso that the PPM 104 may identify which of the base units 114 emitted aparticular audio chirp. Alternatively or additionally, the audio chirpsmay include codes (e.g., audio codes) that uniquely identify the baseunit from which they are emitted.

The PPM 104 and base units 114 may include respective clocks (e.g., thetiming device 205 of FIG. 2 and the timing device 309 of FIG. 3) thatare synchronized with each other to determine propagation delays or timedelays of the audio chirps. The base units 114 may embed timestamps intothe audio chirps based on their respective clocks that indicate the timeat which the base units 114 emitted the audio chirps. The PPM 104 mayuse a timestamp to determine the amount of time (e.g., the propagationdelay or time delay) that lapsed between the time at which one of thebase units 114 emitted an audio chirp and the time at which the PPM 104received the audio chirp.

As shown in FIG. 1C, the audience member 106 and the PPM 104 are locatedwithin the room 115 b at a location at which the PPM 104 determines thatit is a first distance d1 away from one of the base units 114 based onthe audio chirp emitted by that base unit 114 and a second distance d2away from the other one of the base units 114 based on the audio chirpemitted by the other base unit 114. The PPM 104 may determine thedistances d1 and d2 based on the propagation delays of the audio chirpsas described in greater detail below in connection with FIG. 13B. Thedistances d1 and d2 form a first propagation perimeter 174 and a secondpropagation perimeter 176, respectively. The PPM 104 may determine thelocation at which the PPM 104 is disposed within the room 115 b bydetermining the location within the room 115 b at which the propagationperimeters 174 and 176 intersect each other. The base units 114 may bedisposed within the room 115 b at locations that cause the propagationperimeters 174 and 176 to intersect at only one location within theroom. In this manner, a location detection algorithm or process maydistinguish an intersection point 178 of the propagation perimeters 174and 176 that is within the room 115 b from an intersection point 180that is outside of the room 115 b. As described in greater detail belowin connection with FIG. 13B, the PPM 104 may determine its locationwithin the room 115 b based on the uniquely identifiable audio chirps,the timestamp of each audio chirp, and the known location within theroom 115 b of each of the base units 114.

FIG. 2 is a block diagram of the example PPM 104 of FIG. 1A. Asdescribed above, the PPM 104 may be used to monitor the mediaconsumption activities of an audience member (e.g., the audience member106 of FIG. 1A) in addition to location information and motioninformation associated with those media consumption activities. Ingeneral, the PPM 104 includes electronic components configured to detectand collect media monitoring information, location information, andmotion information and communicates the information to the homeprocessing system 120 and/or the central facility 122 (FIG. 1A) forsubsequent analyses. As shown in FIG. 2, the PPM 104 includes aprocessor 202, a memory 204, a timing device 205, a communicationinterface 206, a plurality of media monitoring information sensors 208,a plurality of location and motion sensors 210, a plurality of outputdevices 212, an input interface 214, and a visual interface 216, all ofwhich are communicatively coupled as shown.

The processor 202 may be any processor suitable for controlling the PPM104 and managing or processing monitoring data related to detected mediaconsumption or presentation information, location information, and/ormotion information. For example, the processor 202 may be implementedusing a general purpose processor, a digital signal processor, or anycombination thereof. The processor 202 may be configured to perform andcontrol various operations and features of the PPM 104 such as, forexample, setting the PPM 104 in different operating modes, controlling asampling frequency for collecting media monitoring information, locationinformation, and motion information, managing communication operationswith other processor systems (e.g., the base units 114, the homeprocessing system 120, the server 126 of FIG. 1A), selecting locationinformation systems (e.g., the RF transceiver tower 108, the satellite110, and the base units 114), etc.

The memory 204 may be used to store collected media monitoringinformation, program instructions (e.g., software, firmware, etc.),program data (e.g., location information, motion information, etc.),and/or any other data or information required to operate the PPM 104.For example, after acquiring location information, motion information,and/or media monitoring information, the processor 202 may time stampthe acquired information and store the time stamped information in thememory 204. The memory 204 may be implemented using any suitablevolatile and/or non-volatile memory including a random access memory(RAM), a read-only memory (ROM), a flash memory device, a hard drive, anoptical storage medium, etc. In addition, the memory 204 may be anyremovable or non-removable storage medium.

The timing device 205 may be implemented using a clock (e.g., areal-time clock), a timer, a counter, or any combination thereof. Thetiming device 205 may be used to generate timestamps or used toimplement any timing operations. Although the timing device 205 is shownas separate from the processor 202, in some implementations the timingdevice 205 may be integrated with the processor 202.

The communication interface 206 may be used to communicate informationbetween the PPM 104 and other processor systems including, for example,the base units 114, the home processing system 120, and/or the server126 of FIG. 1A. The communication interface 206 may be implemented usingany type of suitable wired or wireless transmitter, receiver, ortransceiver including a Bluetooth transceiver, an 802.11 transceiver, acellular communications transceiver, an optical communicationstransceiver, etc.

The media monitoring information sensors 208 include an audio sensor218, an optical sensor 220, and an RF sensor 222. The example PPM 104,via the audio sensor 218, the optical sensor 220, and/or the RF sensor222, observes the environment in which the audience member 106 islocated and monitors for media presentation and/or signals associatedwith media presentations. When media presentations are detected via, forexample, media codes, the example PPM 104 logs or stores arepresentation of the media content in the memory 204 and/or identifiesthe content, along with the time at which the content is detected.

The audio sensor 218 may be, for example, a condenser microphone, apiezoelectric microphone or any other suitable transducer capable ofconverting audio information into electrical information. The opticalsensor 220 may be, for example, a light sensitive diode, an infrared(IR) sensor, a complimentary metal oxide semiconductor (CMOS) sensorarray, a charge-coupled diode (CCD) sensor array, etc. The RF sensor 222may be, for example, a Bluetooth transceiver, an 802.11 transceiver, anultrawideband RF receiver, and/or any other RF receiver and/ortransceiver. While the example PPM 104 of FIG. 1A includes the audiosensor 218, the optical sensor 220, and the RF sensor 222, the examplePPM 104 need not include all of the sensors 218, 220, and 222. Forexample, the audio sensor 218 is sufficient to identify audio/video orprogram content via program characteristics, such as signatures or, ifthey are present, audio codes. Additionally, the optical sensor 220 issufficient to identify program content via program characteristics, suchas signatures or, if present, video codes. However, because videomonitoring generally requires a line of sight between the PPM 104 andthe media delivery device, one particularly advantageous exampleincludes the audio sensor 218 and the optical sensor 220.

The location and motion sensors 210 are configured to detectlocation-related information and/or motion-related information and togenerate corresponding signals that are communicated to the processor202. More specifically, the location and motion sensors 210 may includea motion sensor 224, a satellite positioning system (SPS) receiver 226,an RF location interface 228, and a compass 230.

Some of the location and motion sensors 210 may be configured to receivelocation-related information (e.g., encoded information, pluralities offragmented information, etc.) and to perform any processing necessary toconvert the received information to location information that indicatesthe location at which the PPM 104 is located. For example, locationinformation may be derived using triangulation techniques, whereby thePPM 104 may receive RF signals from three or more RF transmitters (e.g.,three or more of the base units 114 of FIG. 1A). In this case, a singleRF signal from any one RF transmitter may be useless for generatinglocation information. However, the location information may be generatedby triangulating or processing a combination of RF signals from aplurality of RF transmitters. Thus, some of the location and motionsensors 210 may be configured to process received location-relatedsignals to generate location information and others of the location andmotion sensors 210 may be configured to process the receivedlocation-related signals in combination with software executed on theprocessor 202 to generate location information. Still others of thelocation and motion sensors 210 may communicate any received informationto the processor 202 for processing.

The motion sensor 224 may be used to detect relatively small bodymovements of an audience member (e.g., the audience member 106),generate motion information related to the body movements, andcommunicate the motion information to the processor 202. The motionsensor 224 may be implemented using any suitable motion detection devicesuch as, for example, a mercury switch, a trembler, a piezo-gyroscopeintegrated circuit (IC), an accelerometer IC, etc.

The motion information generated by the motion sensor 224 may be used todetermine if the audience member 106 is wearing or carrying the PPM 104.In addition, the motion information may be used to determine if theaudience member 106 is actively consuming (e.g., paying attention to) amedia presentation. For example, if the motion information indicatesthat no movement is generated by the audience member 106, an analysis ofsuch motion information may indicate that the audience member 106 wassleeping and, thus, not actively consuming a media presentation.Alternatively, if the motion information indicates that the audiencemember 106 is generating an extraordinary amount of information, ananalysis of such motion information may indicate that the audiencemember is either participating with the media presentation or is movingaround too much to adequately consume the media presentation. In eithercase, analyses of the motion information may be used to prompt theaudience member 106 via one of the output devices 212 to confirm if theaudience member 106 is actively consuming the media presentation.

The SPS receiver (SPSR) 226 may be implemented using, for example, aglobal position system (GPS) receiver and may be configured to generatelocation information based on encoded GPS signals received from GPSsatellites. In general, the SPS receiver 226 may be used by the PPM 104to collect location information in outdoor environments.

The RF location interface 228 may be implemented using a receiver or atransceiver and may be used to receive location-related signals orinformation from location information systems such as, for example, theRF transceiver tower 108 and/or the base units 114. The RF locationinterface 228 may also be configured to broadcast location-relatedinformation such as, for example, time-stamped PPM identification codes.The time-stamped PPM identification codes may be received by, forexample, three or more of the base units 114, which may process thecodes cooperatively using triangulation techniques to determine thelocation of the PPM 104. The base units 114 may communicate to the homeprocessing system 120 the received time-stamped PPM identification codesalong with information relating to the time at which the codes werereceived by each of the base units 114. The home processing system 120may then determine the location of the PPM 104 based on thisinformation.

The RF location interface 228 may be implemented using any suitable RFcommunication device such as, for example, a cellular communicationtransceiver, a Bluetooth transceiver, an 802.11 transceiver, anultrawideband RF transceiver, etc. In addition, the RF locationinterface 228 may be implemented using only an RF receiver or only an RFtransmitter. Examples of known location-based technologies that may beimplemented in cooperation with the RF location interface 228 includethe Ekahau Positioning Engine™ by Ekahau, Inc. of Saratoga, Calif.,United States of America, an ultrawideband positioning system byUbisense, Ltd. of Cambridge, United Kingdom or any of the ultrawidebandpositioning systems designed and/or patented by Multispectral Solutions,Inc. of Germantown, Md., United States of America. Ultrawidebandpositioning systems, depending on the design, offer advantages includinglonger battery life due to lower power consumption, greater precisionand such systems tend to use less of the available signal spectrum.

The Ekahau Positioning Engine™ may be configured to work with aplurality of standard wireless communication protocol base stations(e.g., 802.11, Bluetooth, etc.) to broadcast location-relatedinformation. By implementing the RF location interface 228 using asuitable wireless communication protocol device and communicativelycoupling the base units 114 to the RF location interface 228 using thesame communication protocol, the Ekahau Positioning Engine™ may be usedto generate location information. In particular, location-relatedinformation may be transmitted from the base units 114, received by theRF location interface 228, and used to generate location informationusing Ekahau Positioning software offered by Ekahau, Inc.

The Ubisense ultrawideband system may be used by communicativelycoupling an ultrawideband transmitter to each of the base units 114(FIG. 1A) and implementing the RF location interface 228 using anultrawideband receiver. In this manner, the RF location interface 228can receive ultrawideband location-related information that is broadcastfrom the base units 114 so that the PPM 104 can generate locationinformation based on the received ultrawideband signals.

The compass 230 may be implemented using a magnetic field sensor, anelectronic compass IC, and/or any other suitable electronic circuit. Ingeneral, the compass 230 may be used to generate direction information,which may be useful in determining the direction in which an audiencemember (e.g., the audience member 106) is facing. The directioninformation may be used to determine if a person is facing a televisionto enable consumption of a television program. The direction informationmay also be used to determine if a person is facing, for example, abillboard advertisement so that when the PPM 104 receives an RFidentification signal corresponding to the billboard advertisement andlocation information indicating that the audience member 106 is in frontof the billboard, the direction information from the compass 230 may beused to determine if the audience member 106 is facing the billboard. Inthis manner, the billboard content may be credited appropriately ashaving been consumed by the audience member 106.

An example positioning technology that may be used in combination withthe compass 230, the motion sensor 224, and the SPS receiver 226 is theDead-Reckoning Module (DRM®) produced and sold by Point ResearchCorporation of Santa Ana, Calif. The DRM® is configured to enablegeneration and/or collection of location information within buildings(e.g., the household 102) and in outdoor environments. In general, whenused outdoors, the DRM® uses GPS technology to collect locationinformation. When used indoors, the DRM® uses, among other components, acompass (e.g., the compass 230) and an accelerometer (e.g., the motionsensor 224) to generate location information.

The plurality of output devices 212 may be used to capture the attentionof or alert audience members (e.g., the audience member 106 of FIG. 1A)to, for example, provide information to audience members and/or requestinput. The plurality of output devices 212 includes a speaker 212 a, avibrator 212 b, and a visual alert 212 c.

The speaker 212 a may also be used to communicate with the base units114. In particular, as described in greater detail below in connectionwith FIG. 13A, the speaker 212 a may be used to inform the base units114 that the PPM 104 is within proximity of the base units 114. Thespeaker 212 a may be implemented using any type of acoustic emitter. Forexample, the speaker 212 a may be implemented using a speaker capable ofemitting audio in the human audible range. Alternatively oradditionally, the speaker 212 a may be implemented using a speaker ortransducer capable of emitting ultrasound audio for use with ultrasoundlocation detection systems. Although one speaker is shown in FIG. 2, thePPM 104 may include any number of speakers, each of which may beconfigured to suit a particular function (e.g., a speaker to emitacoustic frequencies in the human audible range and a speaker ortransducer to emit ultrasound frequencies). Base units 114 that are inrooms without media delivery devices (e.g., the media delivery centers112) may broadcast blank media codes or interference codes when the baseunits 114 detect that the PPM 104 is within the room associated with thebase units 114. In this manner, the base units 114 may prevent orsubstantially eliminate the effects of spillover of media codes frommedia delivery devices in other rooms.

The PPM 104 may also include the input interface 214, which may be usedby an operator (e.g., the audience member 106) to input information tothe PPM 104. For example, the input interface 214 may include one ormore buttons or a touchscreen that may be used to enter information, setoperational modes, turn the PPM 104 on and off, etc. In addition, theinput interface 214 may be used to enter PPM settings information,audience member identification information, etc.

The PPM 104 may further include the visual interface 216, which may beused in combination with the input interface 214 to enter and retrieveinformation from the PPM 104. For example, the visual interface 216 maybe implemented using a liquid crystal display (LCD) that, for example,displays detailed status information, location information,configuration information, calibration information, etc. In some cases,the visual interface 216 may include light-emitting diodes (LEDs) thatconvey information including, for example, status information,operational mode information, etc.

FIG. 3 is a block diagram of one of the example base units 114 of FIG.1A. As described above, the example base units 114 may be used tocommunicate information to the PPM 104, the home computer 120, and/orthe central facility 122 of FIG. 1A. As shown in FIG. 3, the examplebase unit 114 includes a processor 302, a memory 304, an RF locationinterface 306, a PPM interface 308, a timing device 309, a remotetransceiver 310, an input interface 312, a visual interface 314, anaudio/video interface 316, a speaker 318, and a microphone 320, all ofwhich may be communicatively coupled as shown.

The processor 302 may be used to control and perform various operationsor features of the base unit 114 and may be implemented using anysuitable processor, including any general purpose processor, digitalsignal processor, or any combination thereof. For example, the processor302 may be configured to receive location information, motioninformation, and/or media monitoring information from the PPM 104. Asdescribed above, information collected by the PPM 104 may be stored inthe memory 204 (FIG. 2). Alternatively, the collected information may bestored in the memory 304 and communicated to the home processing system120 and/or the central facility 122.

The processor 302 may also be configured to control communicationprocesses that occur between the base unit 114 and other processingsystems (e.g., the PPM 104, the home processing system 120, and theserver 126). For example, the processor 302 may provide location-relatedinformation to PPMs via the RF location interface 306. In addition, theprocessor 302 may control the reception of media monitoring information,location information, motion information, etc. from the PPM 104 via thePPM interface 308 and store the information in the memory 304. Theprocessor 302 may then cause the remote transceiver 310 to communicatethe monitoring data to, for example, the home processing system 120(FIG. 1A) and/or the central facility 122 (FIG. 1A) via the remotetransceiver 310.

The memory 304 is substantially similar or identical to the memory 204(FIG. 2) and may be used to store program instructions (e.g., software,firmware, etc.), data (e.g., location information, motion information,media monitoring information, etc.), and/or any other data orinformation associated with the base unit 114.

The RF location interface 306 may be implemented using a transmitter, areceiver, or a transceiver and configured to transmit and/or receivelocation-related information. In addition, the RF location interface 306may be configured to communicate with the RF location interface 228(FIG. 2) of the PPM 104. For example, the RF location interface 306 maytransmit encoded location-related codes to the PPM 104, which mayreceive encoded location-related codes from several of the base units114 to determine location coordinates indicative of the location of thePPM 104. Additionally or alternatively, the RF location interface 306may receive encoded location-related codes from the PPM 104 and, asdescribed above, may work in cooperation with other base units and/orthe home processing system 120 to determine the location of the PPM 104.

The RF location interface 306 may be implemented using any suitable RFcommunication device such as, for example, a cellular communicationtransceiver, a Bluetooth transceiver, an 802.11 transceiver, anultrawideband RF transceiver, etc. In addition, the RF locationinterface 306 may be used in combination with any of the knownlocation-based technologies described above (e.g., the EkahauPositioning Engine™ by Ekahau, Inc. and/or the ultra-widebandpositioning system by Ubisense, Ltd.). Thus, the RF location interface306 may be configured to receive and/or transmit any form oflocation-related information including location coordinates and anyother information associated with known location-based technologies.

The PPM interface 308 is substantially similar or identical to thecommunication interface 206 of FIG. 2 and may be configured tocommunicate information between the base unit 114 and one or more PPMs(e.g., the PPM 104 of FIGS. 1A, 1B, and 2). The PPM interface 308 may beany wired or wireless transceiver such as, for example, a Bluetoothtransceiver, an 802.11 transceiver, an Ethernet transceiver, a UART, acellular communication transceiver, etc.

The base unit 114 may also include the input interface 312 and thevisual interface 314, which may be substantially similar or identical tothe input interface 214 and the visual interface 216, respectively, ofFIG. 2.

The timing device 309 may be substantially similar or identical to thetiming device 205 described above in connection with FIG. 2. Forexample, the timing device 309 may include one or more of a clock (e.g.,a real-time clock), a timer, and a counter. In addition, although shownas separate from the processor 302, the timing device 309 may beintegrated with the processor 302. The timing device 309 may be used bythe base unit 114 to generate timestamps and perform anytime/timing-based operations. Further, the timing device 309 may besynchronized with the timing device 205 of the PPM 104. In this manner,the base unit 114 and the PPM 104 may perform synchronized operations orperform operations that require the base unit 114 and the PPM 104 tohave synchronized clocks.

The remote transceiver 310 may be used to communicate informationbetween the base unit 114 and, for example, the home processing system120 (FIG. 1A) and/or the central facility 122 (FIG. 1A). The remotetransceiver 310 may be communicatively coupled to the network 124 andmay be implemented using any suitable wired or wireless communicationtransceiver including, for example, a telephone modem, a DSL modem, acable modem, a cellular communication circuit, an Ethernet communicationcircuit, an 802.11 communication circuit, etc. The remote transceiver310 may be used to communicate media monitoring information (e.g., audiosamples), location information, and/or motion information to the homeprocessing system 120 and/or the central facility 122 via the network124.

The audio/video interface 316 may be used to obtain audio and/or videoinformation from media delivery centers (e.g., the media deliverycenters 112 of FIG. 1A). The audio/video interface 316 may beimplemented using any wired or wireless technology that enables the baseunit 114 to receive media information associated with mediapresentations presented by the media delivery centers 112. For example,the audio/video interface 316 may be implemented using an RF audio/videoreceiver (e.g., a 2.4 GHZ wireless audio/video receiver), a compositeinterface, an audio RCA interface, an optical interface, etc. Theaudio/video interface 316 may be configured to communicate the receivedaudio and/or video to the processor 302, which may execute a media codeextraction algorithm to extract and log audio and/or video codes fromthe received media. The processor 302 may alternatively or additionallyexecute a signature generation algorithm to generate and storesignatures based on the received media.

The speaker 318 may be used to communicate information to the PPM 104.In particular, the speaker 318 may be used to communicate media codessuch as, for example, blank media codes or interference codes asdescribed in greater detail below in connection with the example methodof FIG. 13A. Interference codes may be broadcast by base units 114 thatare located in rooms or spaces having no media delivery centers toprevent the PPM 104 from detecting media codes from the media deliverycenters 112 (FIG. 1A) that spill over from other rooms.

The microphone 320 may be used to receive audio information associatedwith media presented by the media delivery centers 112 (FIG. 1A) and/orPPM codes emitted by the PPM 104. Audio emitted by the media deliverycenters 112 may be received by the base unit 114 via the microphone 320and processed by the processor 302 to extract and log audio codesassociated with audience member media consumption. Alternatively oradditionally, the base unit 114 may receive PPM codes emitted by the PPM104 to determine if the PPM 104 is within the same room or space as thebase unit 114. For example, the microphone 320 may be implemented usingan ultrasound microphone that is configured to detect ultrasonic signalsemitted by the PPM 104 to determine the location of the PPM 104.Although one microphone is shown in FIG. 3, the base unit 114 may haveany number of microphones, each of which may be configured to be usedfor a particular function. For example, the base unit 114 may include afirst microphone for detecting audio emitted by the media deliverycenters 112 and a second microphone for detecting ultrasound signalsemitted by the PPM 104.

FIGS. 4 and 5 depict example placement square grids overlaid ontoexample plan views of two different representative households 400 and500 in which the methods, apparatus and articles of manufacturedescribed herein may be implemented. As depicted in FIGS. 4 and 5, aplurality of grid markers which correspond to known locations within thehouseholds 400 and 500 (some of which are indicated by the referencenumerals 402 and 502), are positioned in a predetermined pattern orlayout. The grid markers 402 and 502 may be used in combination withlocation detection technologies (e.g., the RF tower 108, the satellite110, and the base units 114) to determine the positions of PPMs (e.g.,the PPM 104) as the PPMs move throughout the households 402 and 502. Thegrid markers 402 and 502 may be used to generate the movement paths 116a-116 c described above in connection with FIG. 1A.

Each of the grid markers 402 and 502 corresponds to a set of coordinates(e.g., geographic coordinates or any other set of information uniquelyrepresenting a physical location) that, in turn, are mapped to knownlocations within the households 400 and 500. For example, thecoordinates of each of the grid markers 402 and 502 may correspond to aparticular room, hallway, or other space or area within the households400 and 500. The grid markers 402 and 502 may be embodied in a databasein the form of a table, a linked list, or any other suitable datastructure accessible by, for example, a processor system within the baseunits 114 (FIG. 1A), the PPM 104 (FIG. 1A), the central facility 122(FIG. 1A), etc. In this manner, location data collected by, for example,the PPM 104 can be mapped, matched, or otherwise translated orcorrelated to particular rooms or other spaces within the households 400and 500, thereby enabling collected media codes and/or signatures to beassociated with particular spaces within which those codes and/orsignatures were collected.

Information uniquely associated with each of the grid markers 402 and502 may be collected using any desired method. For example, one or morePPMs may be configured to detect signals emitted by the one or moreaccess points disposed in the home. Such a process may involve having atechnician carry a PPM, move to each of the grid marker positions, andmeasure/record the signals detected at each grid location and emitted byeach of the access points. The sets of location information may then bestored in tables or other suitable data structures to enable mapping,translation, etc. of subsequently collected location data to knownpositions within the household.

Media delivery centers 404, 406, 408, 504, 506 and 508 may also belocated in one or more of the areas (e.g., rooms, hallways, etc.) of thehouseholds 400 and 500. Each of the media delivery centers 404, 406,408, 504, 506 and 508 may be substantially similar or identical to themedia delivery centers 112 described above in connection with FIG. 1A.While the PPM 104 is collecting media monitoring information, the mediadelivery centers 404, 406, 408 and 504, 506, 508 may be used to presentor playback media content.

While the grid markers 302 and 402 depicted in FIGS. 3 and 4 form asquare grid arrangement (e.g., the grid markers 302 and 402 are locatedat substantially regular intervals or distances from each other), othergrid marker arrangements may be used instead. For example, the gridmarker layouts shown in FIGS. 6 and 7 are radial grid arrangements inwhich the grid markers 302 and 402 are located along radial linesextending within the various spaces (e.g., rooms, hallways, etc.) fromthe media delivery centers 404, 406, 408 and 504, 506, 508.

Still further FIGS. 8 and 9 depict a media center-centric PPM layout inwhich bounded areas 800, 802, 804, 900, 902 and 904 surrounding therespective media delivery centers 404, 406, 408, 504, 506 and 508 areused to define the areas in which media content from each media deliverycenter may be detected by a PPM, regardless of interior walls and otherstructures within the households 400 and 500. The bounded areas 800,802, 804, 900, 902 and 904 may be used to determine locations within thesquare grid arrangements of FIGS. 4 and 5 and/or the radial gridarrangements of FIGS. 6 and 7 at which PPMs (e.g., the grid markers 402and 502 of FIGS. 4 and 5, respectively) may be placed during acharacterization or mapping process.

Audio associated with media content may often radiate, extend, orotherwise propagate through walls and doors within a building orstructure. As shown in FIGS. 8 and 9, the bounded areas 800, 802, 804,900, 902 and 904 cover portions of two or more rooms or spaces withinthe respective households 400 and 500. Data or media monitoringinformation collected by PPMs located within an overlapping region oftwo of the bounded areas 800, 802, 804, 900, 902 and 904 may correspondto media content presented by the media delivery centers correspondingto those two bounded areas. For example, a PPM located within anoverlapping region of the bounded areas 800 and 802 (FIG. 8) may collectaudio data or media monitoring information associated with the mediadelivery centers 404 and/or 406.

In addition, the bounded areas 800, 802, 804, 900, 902 and 904 may beused to determine areas within the households 400 and 500 that are proneto spillover effects. For example, spillover effects may becharacterized by placing a PPM in a hallway area of the household 400within the bounded area 804 (FIG. 8), presenting media content via themedia delivery center 408, collecting media monitoring information viathe PPM, and analyzing the media monitoring information for audio datacorresponding to the media content presented by the media deliver center408.

FIG. 10 depicts a detailed view of an example bounded area 1000 that maybe used to implement the bounded areas 800, 802, 804, 900, 902 and 904of FIGS. 8 and 9. The example bounded area 1000 of FIG. 10 includes anexample grid arrangement 1002 that may be used to implement the squareand radial grid areas of FIGS. 4-7 and to define a plurality of gridmarkers 1004. The grid markers 1004 may be substantially similar oridentical to the markers 402 and 502 of FIGS. 4-7. The example boundedarea 1000 also includes a plurality of coordinate identifiers 1006 thatmay be used to identify locations within the example grid arrangement1002 at which the grid markers 1004 are located.

As shown by the example grid arrangement 1002 of FIG. 10, the gridmarkers 1004 may be distributed in any grid-like arrangement surroundinga media delivery center 1008, which may include, for example, atelevision 1010. More or fewer grid markers 1004 arranged in any desiredpattern may be used instead of the particular number and arrangement ofposition markers shown in FIG. 10.

The plurality of coordinate identifiers 1006 may be used to tag themedia monitoring information or data collected by the PMM 104 withlocation information identifying the grid markers 1004 at or near thelocation at which the PMM 104 is located. One advantage of a mediacenter-centric layout approach is that the information provided by usingsuch a layout (as represented by example in FIG. 10) may be used as atemplate for visually displaying aggregate test results derived from aplurality of test households.

FIGS. 11A through 14E are example methods that may be used to managesignal (e.g., audio code) spillover in an audience monitoring system.The example methods may be implemented in software, hardware, and/or anycombination thereof. For example, the example methods may be implementedin software that is executed on the PPM 104 of FIGS. 1A and 2, the baseunits 114 of FIGS. 1A and 3, and/or the central facility 122 of FIG. 1A.Although, the example methods are described below as a particularsequence of operations, one or more operations may be rearranged, added,and/or removed to achieve the same or similar results as those describedherein.

FIGS. 11A-11C are flow diagrams of example methods that may be used tocollect time-stamped location information (FIG. 11A) and time-stampedmedia monitoring information (FIG. 11B) using a PPM (e.g., the PPM 104of FIGS. 1A and 2), and combine corresponding time-stamped locationinformation and time-stamped media monitoring information (FIG. 11C).More specifically, the example methods of FIGS. 11A and 11B may beperformed by a PPM (e.g., the PPM 104 of FIGS. 1A and 2) and the examplemethod of FIG. 11C may be performed by a central processing system(e.g., the home processing system 120 and/or the server 126 of FIG. 1A).Each of the example methods of FIGS. 11A and 11B may be performed by thePPM 104 completely independently of the other or one or more of theblocks that are common to both methods may be performed by the PPM 104 asingle time for the benefit of both methods. For example, the PPM 104may be configured to generate a single set of time stamps that are usedin both the method of FIG. 11A and the method of FIG. 11B instead ofrequiring the generation of two separate sets of time stamps.Alternatively, if media monitoring data is collected (using the methodof FIG. 11B) at a frequency that is different from the frequency used tocollect location information (via the method of FIG. 11A), thentimestamps may be generated at the higher of these two frequencies andhave a one to one correspondence with the data collection that occurs atthis higher frequency, whereas only a subset of these timestamps need beassociated with the data collection that occurs at the lower of the twofrequencies. In this, or any other manner, one or more of the blocksassociated with the method of FIG. 11A may be synchronized with theperformance of one or more of the blocks of FIG. 11B.

Turning in detail to the example method of FIG. 11A, the PPM 104 (FIG.1A) obtains location data (block 1102). The PPM 104 may obtain thelocation data from any location information system such as, for example,the RF transceiver tower 108 (FIG. 1A), the satellite 110 (FIG. 1A),and/or the base units 114 (FIG. 1A). Additionally or alternatively, thelocation data may be received from the motion sensor 224 (FIG. 2) and/orthe compass 230 (FIG. 2) for use with, for example, the DRM® describedabove in connection with FIG. 2 to generate location information.

The PPM 104 then generates location information (block 1104) based onthe location data received in connection with block 1102. For example,the location information may be generated using triangulationalgorithms, location data decoding algorithms, interpolation algorithms,and/or any other suitable algorithm for generating location informationbased on the received location data. By way of further example, if asystem similar to the Ekahau system is employed, the location data maybe obtained by measuring the strengths associated with five differentsignals, each received from one of five Ekahau signal emitters disposedin the household. The strengths of the five signals can then be used toidentify the location of the PPM 104 on the household grid (e.g., gridsdescribed in connection with FIGS. 1B, 4, 5, 6, 7, and 10).Specifically, upon generation of the household grid, a set of signalstrength readings are taken at each of the marker locations on the gridand each set of signal strengths is unique to the location of the markerlocation at which the reading was taken. As a result, each unique set ofsignal strengths either corresponds directly to a marker location, orinterpolation can be used to identify a location positioned between oneor more grid markers when a set of signal strengths are collected thatdo not correspond exactly to the signal strength data associated withone of the grid markers.

After generating the location information, the PPM 104 generates atimestamp (block 1106) associated with the time at which the PPM 104obtained the location data in connection with block 1102 and timestampsthe location information (block 1108). The time-stamped locationinformation is then stored (block 1110) in, for example, the memory 204(FIG. 2).

The PPM 104 then communicates the stored time-stamped locationinformation to a central processing system (e.g., the home processingsystem 120 or the server 126 of FIG. 1A) (block 1112). For example, thePPM 104 may be configured to communicate the stored time-stampedlocation information at designated times (e.g., a periodic interval)and/or when a certain number of time-stamped location informationentries have been stored. In an alternative configuration, the PPM 104may be designed to obtain and time stamp location data which may then betransmitted to a central processing system that may be tasked withgenerating location information corresponding to each of the sets oflocation data collected by the PPM 104.

FIG. 11B is a flow diagram of an example method that may be used tocollect time-stamped media monitoring information associated with mediaconsumed by audience members (e.g., the audience member 106 of FIG. 1A).The example method of FIG. 11B may be implemented using the PPM 104(FIGS. 1A, 1B, and 2) and/or one or more of the base units 114 (FIGS. 1Aand 3). The example method of FIG. 11B may be executed by the PPM 104which is configured to detect the presence of a media signal (block1130) emitted by any of the media delivery centers installed in thehousehold (e.g., one of the media delivery centers 112 of FIG. 1A). Ofcourse, if the example method of FIG. 11B is performed by one or more ofthe base units 114, one of the base units 114 may be configured todetect a media signal at block 1130. Depending on the capabilities ofthe PPM 104, the media signal detected may be in an audio, a video, or aRF form and may be detected using a decoding technique or a signaturegeneration technique or any other known technique.

The PPM 104 uses the detected media signal to generate media monitoringinformation (block 1132). For example, the PPM 104 may identify andextract audio codes from the audio portion of a media presentation.Alternatively or additionally, the PPM 104 may generate signatures basedon the received audio and/or video signals.

The PPM 104 may generate a timestamp (block 1134) that indicates thetime at which the PPM 104 received the audio and/or video signal,associate the media monitoring information with the time stamp (block1136) and then store the time-stamped media monitoring information(block 1138) in, for example, the memory 204 (FIG. 2).

The PPM 104 may then communicate the stored time-stamped mediamonitoring information to a central processing system (e.g., the homeprocessing system 120 and/or the server 126 of FIG. 1A) (block 1140).For example, the PPM 104 may be configured to communicate the storedtime-stamped media monitoring information at designated times or when acertain number of time-stamped media monitoring entries have beenstored. In an alternative configuration, the PPM 104 may be configuredto obtain and time stamp media signals (or portions of media signals)which may then be transmitted to the central processing system 122and/or the server 126 that may be tasked with generating mediamonitoring information corresponding to each of the collected mediasignals.

FIG. 11C is a flow diagram of an example method that may be used toanalyze the time-stamped location information and the time-stamped mediamonitoring information collected in connection with the example methodsof FIGS. 11A and 11B. The example method of FIG. 11C is described belowas being performed by a central processing system (e.g., the homeprocessing system 120 or the server 126 of FIG. 1A). However, theexample method may alternatively be performed entirely or in part by thePPM 104 (FIGS. 1A and 2). Additionally or alternatively, the examplemethod of FIG. 14C may be performed in a cooperative manner by a centralprocessing system and the PPM 104.

Initially, a central processing system (e.g., the home processing system120 or the server 126 of FIG. 1A) obtains the time-stamped locationinformation and the time-stamped media monitoring information (block1160) from the PPM 104. The information may be stored in a memory suchas, for example, the mass storage memory 1725 of FIG. 17. Of course, ifthe example method of FIG. 14C is performed by the PPM 104, the PPM 104may be configured to obtain the time-stamped location information andthe time-stamped media monitoring information at block 1160 by, forexample, retrieving the information from the memory 204 (FIG. 2).

During execution of an information merging routine, the centralprocessing system obtains a next time-stamped location information(block 1162). During a first retrieval of location information, theoperation of block 1162 retrieves the first time-stamped locationinformation from a given group of location information entries. Thesystem then determines if corresponding time-stamped media monitoringinformation exists for the time-stamped location information retrievedat block 1162 (block 1164). The system may determine if correspondingtime-stamped media monitoring information exists for the time-stampedlocation information by extracting or identifying the timestamp from thetime-stamped location information, comparing the timestamp with thetimestamps of the time-stamped media monitoring information entries, andidentifying a time-stamped media monitoring information entry if thetimestamp of the time-stamped media monitoring information is within apredetermined time threshold of the timestamp corresponding to thetime-stamped location information. Predetermined time thresholds mayindicate, for example, that location information and media monitoringinformation correspond to one another if the location information iscollected within, for example, one second of the time at which mediamonitoring information is collected.

If it is determined at block 1164 that a time-stamped media monitoringinformation entry does not exist for the time-stamped locationinformation thereby indicating that the PPM 104 was not exposed to anymedia while positioned at the location represented by the locationinformation, control is passed back to block 1162.

Otherwise, the corresponding time-stamped media monitoring informationis obtained (block 1166) and it is determined whether the locationrepresented by the location information is within viewing proximity of amedia delivery device (block 1168), such as, for example, a television.The grid layouts described above in connection with FIGS. 1B, 4-7, andFIG. 10 may be used to determine if the location is within viewingproximity of a media delivery device by comparing the time-stampedlocation information with grid markers (e.g., the grid markers 156, 402,502, and 1004) and determining if the grid marker corresponding to thetime-stamped location information is within a space or area containing amedia delivery device.

If the location represented by the location information is not withinviewing proximity of a television, then the corresponding mediamonitoring information is likely associated with media that “spilledover” or emanated from an area in the household that is outside of theviewing proximity of the audience member 106 carrying the PPM 104. As aresult, the media monitoring information is likely associated with mediathat was not viewed by the audience member 106 carrying the PPM 104 andis, therefore, modified to indicate that it should be disregarded (block1170) (e.g., not credited with viewing). Then the modified mediamonitoring information is merged with the corresponding time-stampedlocation information (block 1172). After merging, the data is stored asan entry in, for example, the mass memory storage 1725 (FIG. 17) (block1174). Alternatively, instead of modifying the media monitoringinformation deemed to be associated with spillover, the method mayinstead cause the media monitoring information to be discarded and/orremoved from memory such that the merging and storing operations neednot be performed. The decision about whether to keep or discard mediamonitoring information associated with spillover depends on whetherspillover data is of interest to those performing the audiencemeasurement process.

If, instead, it is determined at block 1168 that the locationrepresented by the location information is within viewing proximity of atelevision, then the corresponding media monitoring information isdeemed to be associated with media that was actually viewed by theaudience member 106 carrying the PPM 104 and, therefore, is not modified(nor discarded) before being merged with the corresponding time stampedlocation information (block 1172) and stored in the memory 1725 (block1174).

It is then determined whether there are any remaining entries to beprocessed (block 1176). If there are remaining entries to be processed,control is passed back to block 1162. Otherwise, the process is ended.

FIG. 12A is a flow diagram of an example method that may be used todetermine when a PPM (e.g., the PPM 104 of FIGS. 1A and 2) is in a roomor space void of any media delivery centers (e.g., the media deliverycenters 112 of FIG. 1A). The example method of FIG. 12A may be executedon the PPM 104 by, for example, the processor 202 described above inconnection with FIG. 2 and may be configured to work in combination withthe base units 114 (FIGS. 1A and 3). More specifically, the examplemethod of FIG. 12A is configured to detect media codes and determine ifthe media codes are associated with media presented by one of the mediadelivery centers 112. As described in greater detail above, base units114 located within rooms or spaces having no media delivery centers(e.g., the room 115 a of FIG. 1A) may be configured to emit or broadcastinterference media codes or blank media codes to prevent spillover ofmedia codes broadcast by the media delivery centers 112 located in otherrooms or spaces. For example, the interference media codes or blankmedia codes can be emitted at a particular frequency, a particularsignal strength level, etc. that masks media codes broadcast by themedia delivery centers 112 in other locations and that would otherwiseproduce spillover.

Initially, the PPM 104 enters a monitoring mode (block 1202) and detectsa media code (block 1204). Next, the PPM 104 determines whether themedia code is an interference media code (block 1206). If it isdetermined that the media code is an interference media code, the mediacode is discarded or disregarded and control is passed back to block1204. If, instead, it is determined at block 1206 that the media code isnot an interference media code, time-stamped media monitoringinformation is generated and stored (block 1208) in, for example, thememory 204 of FIG. 2. Alternatively, interference media codes identifiedas such at block 1206 may be stored with a corresponding time stamp andinformation indicating that the codes do not represent monitored mediaat block 1208.

FIG. 12B is a flow diagram of an example method that may be used togenerate media monitoring information based on the location of the PPM104. The example method of FIG. 12B may be implemented using the roomdifferentiators 118 a and 118 b described above in connection with FIG.1A, which may emit or broadcast location signals, each having arespective signal characteristic indicative of the room within whicheach is located. For example, the signal characteristic may be aparticular signal frequency or an ancillary location code that can beused to associate each of the location signals to its respective room orlocation. As the PPM 104 is moved between rooms or locations (e.g., therooms 115 a, 115 b, and 115 c), the PPM 104 may receive location signalsemitted by the room differentiators 118 a and 118 b (one of which is aspillover location signal) and media signals (e.g., ancillary audiocodes) associated with media presentations (some of which are spillovermedia signals). The PPM 104 may use the location signals to determine inwhich location or room the PPM 104 is located and may then generatemedia monitoring information based on the received media signals and theidentified location.

Turning in detail to the flow diagram of FIG. 12B, initially the PPM 104receives a media signal (block 1210). For example, the PPM 104 maydetect a media signal associated with an audio portion of a mediapresentation emitted by one of the media delivery centers 112 (FIG. 1A).If the PPM 104 receives two or more media signals at block 1210, the PPM104 may compare the signal strengths, amplitudes, or volumes of each ofthe media signals to one another and discard or disregard the spillovermedia signals having relatively less signal strength, amplitude, orvolume. The PPM 104 may then digitize and store the media signal havingthe relatively greater signal strength, amplitude, or volume. The PPM104 then receives a first location signal (block 1212) and a secondlocation signal (block 1214). For example, the first location signal maybe emitted by the room differentiator 118 a and the second locationsignal may be emitted by the room differentiator 118 b.

The PPM 104 then determines the signal characteristics associated withthe location signals received at blocks 1212 and 1214 (block 1216). Inparticular, the PPM 104 determines a signal strength associated witheach of the received location signals. The PPM 104 may also detect aparticular frequency or ancillary location code associated with each ofthe location signals. The PPM 104 then compares the signal strengths ofthe location signals to one another (block 1218) and selects thelocation signal having the relatively stronger signal strength (block1220) by, for example, discarding or disregarding the spillover locationsignal having relatively less signal strength. Tuning the roomdifferentiators 118 a and 118 b to emit or broadcast location signalsusing relatively low power causes the location signals to besubstantially attenuated by walls (e.g., the wall 119 of FIG. 1).Accordingly, location signals that do propagate through a wall (e.g.,spillover location signals) will have substantially reduced power orsignal strength. The PPM 104 may use the operations of blocks 1218 and1220 and the attenuation effect to determine which of the receivedlocation signals is a spillover signal and which is associated with theroom or location in which the PPM 104 is located and then discard ordisregard the spillover location signal associated with the relativelylower signal strength.

The PPM 104 then generates location information based on the signalcharacteristics determined at block 1216 (block 1222) that areassociated with the location signal having relatively stronger signalstrength as determined at block 1218. For example, the PPM 104 may usethe frequency or the ancillary location code determined at block 1216 todetermine the location identification or room identification of thelocation or room within which the PPM 104 is located. In an exampleimplementation, the PPM 104 may include a data structure (e.g., alook-up table) stored in memory (e.g., the memory 204 of FIG. 2) havinglocation or room identifications and associated frequency values orancillary location codes. In this manner, the PPM 104 may retrieve theroom or location identification from the memory 204 based on thefrequency of the ancillary location code.

The PPM 104 then determines whether a media delivery device (e.g., oneof the media delivery centers 112) is located within the room orlocation indicated by the location information determined at block 1222(block 1224). For example, the PPM 104 may have another data structurestored in the memory 204 having location or room identifications andinformation (e.g., flags, bits, etc.) indicative of whether the mediadelivery centers 112 are located within the rooms or locationsassociated with the location or room identifications. If the PPM 104determines that one of the media delivery centers 112 is located withinthe room or location indicated by the location information, then the PPM104 generates media monitoring information based on the media signalreceived at block 1210 (block 1226). For example, the PPM 104 mayextract an ancillary audio code from the media signal or may generate anaudio signature based on the media signal. The PPM 104 may then generateand store time-stamped, location-annotated media monitoring information(block 1228). For example, the PPM 104 may use the timing device 205(FIG. 2) to generate a time stamp indicative of the time at which thePPM 104 received the media signal at block 1210, and the PPM 104 maythen concatenate or merge the time stamp, the location information, andthe media monitoring information to generate the time-stamped,location-annotated media monitoring information. The PPM 104 may thenstore the time-stamped, location-annotated media monitoring informationin the memory 204.

After the PPM 204 has stored the time-stamped, location-annotated mediamonitoring information at block 1228 or if the PPM 104 determines atblock 1224 that one of the media delivery centers 112 is not locatedwithin the room or location indicated by the location information, thenthe process is ended. Of course, control may alternatively be returnedto the operation of block 1210 when the PPM 104 receives another mediasignal, and the PPM 104 may repeat the operations of the example methodof FIG. 12 b.

Although the example method is described above as using the PPM 104 toperform all of the operations depicted in the flow diagram of FIG. 12B,in other example implementations, the example method may be implementedusing a combination of the PPM 104 and another processor system (e.g.,the home processing system 120 or the server 126 of FIG. 1). Forexample, the PPM 104 may obtain the media signal at block 1210 and thelocation signals at block 1212 and 1214, store the same in the memory204 (FIG. 2), and subsequently communicate a plurality of stored mediasignals (e.g., digitized media signals) and respective location signalsto another processor system. The other processor system may then performthe remaining operations depicted in the flow diagram of FIG. 12B togenerate and store the time-stamped, location-annotated media monitoringinformation based on the media signals and location signals as describedabove.

FIG. 13A is a flow diagram of an example method that may be used tooutput interference media codes by base units (e.g., the base units 114of FIGS. 1A and 3). In general, the example method of FIG. 13A may beused in combination with the example method described above inconnection with FIG. 12A to prevent the PPM 104 (FIG. 1A) from detectingmedia codes that spill over into rooms having no media delivery centers(e.g., the media delivery centers 112 of FIG. 1A) when the PPM 104 islocated within that room. More specifically, the example method of FIG.13A may be used to broadcast or emit interference media codes via thebase unit 114 based on the proximity of the PPM 104 to the base unit114. The example method of FIG. 13A described below may be implementedin the base units 114 located in rooms or spaces having none of themedia delivery centers 112. For example, the example method may beimplemented in the base unit 114 located in the room 115 a of FIG. 1A.

Initially, the base unit 114 enters a monitoring mode (block 1302). Themonitoring mode of the base unit 114 is configured to monitor for thepresence of the PPM 104 by, for example, detecting audio chirps from thePPM 104 that may be inaudible to the human ear. The audio chirps may bebroadcast by the PPM 104 via, for example, the speaker 212 a describedabove in connection with FIG. 2 and may include PPM codes that are usedto inform the base unit 114 when the PPM 104 is within the same room orspace as the base unit 114.

The base unit 114 then obtains a PPM code (block 1304) via an audiochirp emitted by the PPM 104 and determines the proximity of the PPM 104(block 1306). The base unit 114 may determine the proximity of the PPM104 by measuring the volume of the audio chirp. Additionally oralternatively, the PPM 104 and the base unit 114 may includesynchronized clocks (e.g., the timing device 205 of FIG. 2 and thetiming device 309 of FIG. 3) and the PPM 104 may timestamp the audiochirp so that when the base unit 114 receives the audio chirp the baseunit 114 may determine the delay between the transmission of the audiochirp by the PPM 104 and the reception of the audio chirp by the baseunit 114 and, thus, determine the proximity of the PPM 104 based on thetransmission propagation delay. Another example method for determiningthe proximity of the PPM 104 to the base units 114 is described below inconnection with FIG. 13B and involves configuring the base units 114 toemit the audio chirps and the PPM 104 to detect the audio chirps.

After the base unit 114 has determined the proximity of the PPM 104, thebase unit 114 may then determine an output level (e.g., a power level,volume, etc.) at which to output the interference media code (block1308). If the interference media code is output by the base unit 114 viaaudio, then the base unit 114 may determine a volume level at which toemit the interference media code. Of course, if the interference mediacode is output by the base unit 114 via RF, the base unit 114 maydetermine an RF signal strength level or power level at which to emitthe interference media code.

The base unit 114 then emits the interference media code at thedetermined level (block 1310). The base unit 114 may output interferencemedia codes while monitoring for audio chirps from the PPM 104 in amanner that prevents the PPM 104 from detecting media codes emitted bymedia delivery centers 112 located in other rooms or spaces.

It is then determined whether the base unit 114 is to obtain another PPMcode (block 1312). If another PPM code is to be obtained, control ispassed back to block 1304. For example, the base unit 114 may beconfigured to monitor for the presence of PPM codes for a predefinedlength of time. If a PPM code is detected in that time period, then thatdetected PPM code is captured at the block 1304. If, instead, no suchPPM code is detected during the predefined length of time, then the baseunit 114 may be configured to enter a reduced monitoring mode in whichthe base unit 114 cycles between periods of monitoring activity andperiods of inactivity. The frequency at which the base unit 114 cyclesbetween a monitoring state and a state of inactivity is selected suchthat the likelihood of not detecting a PPM that has entered themonitoring proximity of the base unit 114 is negligible. The monitoringproximity of the base unit 114 is the area proximate to the base unit114 within which the presence of a PPM is detectable by the base unit114 (i.e., the area representing the monitoring reach of the base unit114).

FIG. 13B is a flow diagram of an example method that may be used todetermine the location of a PPM (e.g., the PPM 104 of FIGS. 1A-1C)within a room (e.g., the room 115 b of FIG. 1C). The location of the PPM104 may be determined based on the proximity of the PPM 104 to one ormore base units (e.g., the base units 114 of FIGS. 1C and 3) as shown inFIG. 1C. The example method of FIG. 13B may be used at least in part toimplement the operation of block 1306 described above in connection withFIG. 13A. The example method is described below in connection with theexample location detection system 172 of FIG. 1C. Specifically, apropagation delay or time delay is determined by the PPM 104 for eachaudio chirp received from each base unit 114. Each time delay is thenmultiplied by the speed of sound to calculate the distance between thePPM 104 and the base units 114. Although the audio chirps are describedbelow as emitted from the base units 114 and received by the PPM 104, inan alternative implementation, the audio chirps may be emitted from thePPM 104 and received by the base units 114 that may then use theresulting information to perform distance calculations (e.g., determinethe distances d1 and d2 of FIG. 1C). In yet another alternativeimplementation, the PPM 104 and the base units 114 may all be adapted toemit audio chirps and detect audio chirps and to use the resultinginformation to perform distance calculations.

Now turning in detail to FIG. 13B, the base units 114 each emit an audiochirp and associated timestamps in a synchronized manner (block 1332).For example, the first base unit 114 emits a first audio chirp at a timeT1 and the second base unit 114 emits a second audio chirp at a time T2.The times T1 and T2 are offset from each other by a substantially shorttime period spanning, for example, tenths of a second or less. In oneexample, the base units 114 may generate the timestamps for T1 and T2using their respective clocks (e.g., the timing device 309 of FIG. 3)and may encoded each timestamp in their respective audio chirps. Inanother example, the base units 114 may emit audio chirps atpredetermined or preprogrammed times and the PPM 104 may bepreprogrammed with information about the times of emissions of the audiochirps. For example, clocks of the PPM 104 and the base units 114 (e.g.,the timing device 205 of FIG. 2 and the timing device 309 of FIG. 3) maybe synchronized with each other, and the base units 114 may beconfigured to emit the audio chirps at pre-designated times that areknown to the PPM 104.

In yet another example, the base units 114 may be configured to generatean RF signal a predefined or predetermined period of time prior toemitting an audio chirp. In this case, the RF signal acts as a pulsesignal to synchronize the operation of the PPM 104 and the base units114. More specifically, each of the base units 114 may be configured toemit an RF signal that is detectable by the PPM 104 and subsequently,after a predetermined period of time has lapsed (e.g., 500 ms, 1 s, 2 s,etc.), emit an audio chirp. A time value representing the predeterminedperiod of time may be stored in the PPM 104 or may be communicated inthe RF signal. In any case, the PPM 104 is configured to obtain thepredetermined period of time value upon receipt of the RF signal. Inthis manner, when the PPM 104 obtains an RF signal from the first baseunit 114, the PPM 104 may read or otherwise obtain a time value from itsclock (e.g., the timing device 205 of FIG. 2) and determine the time T1by adding the predetermined period of time to the time value. The PPM104 may then determine the time T2 in a similar manner when it receivesan RF signal from the second base unit 114. The times T1 and T2 may thenbe stored in memory (e.g., the memory 204 of FIG. 2) for subsequentretrieval.

The PPM 104 detects the first audio chirp at a time T3 and the secondaudio chirp at a time T4 (block 1334). The times T3 and T4 may bedetermined by generating a timestamp based on the clock (e.g., thetiming device 205 of FIG. 2) of the PPM 104 when each of the first andsecond audio chirps are received. The PPM 104 then obtains thetimestamps T1 and T2 associated with each of the audio chirps (block1336). For example, the timestamps T1 and T2 may be extracted from theaudio chirps or retrieved from memory (e.g., the memory 204 of FIG. 2)if, for example, the PPM 104 is preprogrammed with the times at whichthe base units 114 emit the audio chirps. Regardless of how thetimestamps are provided to the PPM 104, the PPM 104 is configured tothen determine the time of flight of each of the first and second audiochirps (block 1338). The time of flight is the propagation delay or thetime delay between the times at which the audio chirps were emitted bythe base units 114 (e.g., times T1 and T2) and the times at which theaudio chirps were detected by the PPM 104 (e.g., times T3 and T4). ThePPM 104 may determine the time of flight of the first audio chirp bysubtracting the time T3 from the time T1 and may determine the time offlight of the second audio chirp by subtracting the time T4 from thetime T2.

The PPM 104 may use the time of flight information to calculate thedistance traveled (e.g., the distances d1 and d2 of FIG. 1C) by each ofthe first and second audio chirps (block 1340). For example, thedistances d1 and d2 traveled by the audio chirps may be determined bymultiplying the time of flight for each audio chirp by the speed ofsound. The distances d1 and d2 may be used to represent the proximity ofthe PPM 104 to each of the base units 114. The operations of blocks 1338and 1340 may be adapted to implement the operation of block 1306described above in connection with FIG. 13A to determine the proximityof the PPM 104 to one or more base units 114.

The PPM 104 may then determine a propagation perimeter for each of thedistances d1 and d2 and the intersection point within the room 115 b ofthose propagation perimeters (block 1342). For example, the distances d1and d2 traveled by the first and second audio chirps may be used by thePPM 104 to determine the propagation perimeters 174 and 176 shown inFIG. 1C. The propagation perimeters 174 and 176 are represented ascircular patterns, each having a radius equal to one of the distances d1and d2 and a center located at the position at which its associated baseunit 114 is disposed. The PPM 104 may then determine, based on the knownlocation of the base units 114 within the room 115 b and the distancesd1 and d2, that the propagation perimeters 174 and 176 intersect eachother at the intersection point 178 within the room 115 b as shown inFIG. 1C.

The PPM 104 then determines its location within a room (e.g., the room115 b) (block 1344). The PPM 104 may determine its location based on thedistances d1 and d2 and the intersection of the propagation perimeters174 and 176. For example, the PPM 104 may determine that location atwhich that the propagation perimeters 174 and 176 intersect with eachother within the room 115 b defines its location within the room 115 b.

The example method described above may be performed in real-time by thePPM 104 and/or the base units 114. Alternatively, the informationassociated with audio chirps and the timestamps T1, T2, T3, and T4 maybe stored in the PPM 104 and/or the base units 114 and communicated toanother processing system (e.g., the home processing system 120 of FIG.1A) in real-time or at a later time. The information may then beprocessed by the other processing system in a real-time process or in apost-process. Further, the techniques described hereinabove fordetermining the location of the PPM 104 using audio chirp signalsemitted by one or more of the base units 114 disposed in the household102 or a room (e.g., the room 115 b of FIGS. 1A-1C) of the household 102may, but need not be performed in connection with the base units thatemit interference codes described above in connection with FIG. 13A. Aswill be appreciated by one having ordinary skill in the art, thetechniques described hereinabove for determining the location of the PPM104 using audio chirp signals emitted by one or more of the base units114 may also be performed for the more general purpose of identifyingthe location of the PPM 104 for purposes of combating spilloverassociated with media presented anywhere in the household 102 or in anyother indoor location, including, for example, any type of dwelling orresidence, office space, retail location, etc.

FIG. 14A-14E are flow diagrams of example methods that may be used toenhance the accuracy of the location information detected using the PPM104 by determining whether two sequentially detected locations that areassociated with different rooms in the household are actually associatedwith movement of the audience member 106 between the two rooms or areinstead caused by the imprecision of the location detection equipmentinstalled in the PPM 104. More specifically, and referring also to FIG.1B, location data collected by the PPM 104 while located at a firstposition near the wall 119 in a room (e.g., the room 115 c) may,depending on the accuracy of the location detection equipment used,identify or represent a second position located on the opposite side ofthat wall 119 such that the location data erroneously indicates that theaudience member 106 carrying the PPM 104 is located in a second room(e.g., the room 115 a) that is adjacent to the first room 115 c. Severaltechniques may be deployed to identify erroneous location data of thistype including: 1) a technique involving an examination of individuallocation data values, 2) a technique involving the calculation of a rateof speed of a person carrying a PPM, 3) a technique involving thecollective examination of several location data values to identify adirection of travel of the audience member 106 carrying the PPM 104, and4) a technique involving the identification of sequentially collectedlocation data that are clustered within a predefined distance from awall that separates two adjacent rooms.

With reference to FIG. 14A, a technique involving an examination ofindividual location data values may involve, for example, processinglocation information to identify sequentially collected location datapoints that represent locations disposed in different rooms (e.g., therooms 115 a-c of FIGS. 1A and 1B) in a household (e.g., the household102 of FIGS. 1A and 1B). Sequentially collected location data pointsmeeting this criteria cause one or more subsequently collected locationdata points to be examined to determine whether the audience member 106likely moved between the rooms (as indicated by the location data),thereby suggesting that the location data is erroneous. Depending onwhether movement between the rooms likely occurred, the location dataindicating a room change is treated as either accurate or erroneous andused by the PPM 104, the home processing system 120, and/or the server126 (FIG. 1A) to accurately credit media exposure that occurred ineither room, if any.

The method of FIG. 14A may be performed using any of a number of dataprocesses and may be implemented using a PPM (e.g., the PPM 104 of FIG.1A) or using a PPM in combination with a central processing system(e.g., the home processing system 120 or the server 126 of FIG. 1A) toprocess a set of sequentially-collected location information obtained bythe PPM 104. The location information is converted into sets of locationcoordinates that are each used to identify the location of the PPM 104within a home (e.g., the household 102 of FIG. 1A) at the time that eachof the sets of location coordinates was obtained. Each of the sets oflocation coordinates are represented using two values, a firstrepresenting an X coordinate and a second representing a Y coordinate,wherein the floor plan of the household 102 is mapped to an XY grid asshown in FIG. 1B. A counting variable (n) is used to identify an indexof each collected location coordinate indicating the order or sequencein which each of the sets of location coordinates are collected. Forexample, when n is equal to one, the coordinate set (X_(n), Y_(n))represents the first of the sets of location coordinates in the sequenceof collected location coordinates. Likewise, when n=2, the coordinateset (X_(n), Y_(n)) represents the second of the sets of locationcoordinates in the sequence, and so on. As discussed above, a timestampreflecting the time at which a particular set of location coordinateswas collected is stored in a memory and associated with thecorresponding set of location coordinates. Referring still to FIG. 1B,each of the location coordinates is used to identify a room in which thePPM 104 was located at the time that the location coordinate wascollected. The room corresponding to each location coordinate may beidentified using, for example, a look-up table that relates eachpossible location coordinate with the room in which that locationcoordinate is disposed. Each set of location coordinates and itscorresponding room is stored in a memory (e.g., the memory 204 of FIG.2) along with the corresponding timestamp at which the set of locationcoordinates was collected. Sequentially collected location coordinatesand their corresponding rooms are then compared to determine whether thesequentially collected location coordinates indicate that the audiencemember 106 has moved from one room (e.g., the first room 115 c) in thehousehold 102 to another room (e.g., the second room 115 a) in thehousehold during the time elapsing between the collection of thesequentially collected sets of location coordinates.

In the example method of FIG. 14A, the processing begins with thecollection of the location information and timestamps (block 1402). Forexample, the location information may be collected from a locationinformation system such as the RF tower 108, the satellite 110, and/thebase units 114 (FIG. 1A). The timestamps may also be collected from thelocation information systems or may be generated by the PPM 104. Thelocation information is converted to sets of location coordinates (block1404) and the sets of location coordinates are stored in a memory (e.g.,the memory 204 of FIG. 2) (block 1406). Each set of location coordinatesis also stored or associated with information representing thesequential order in which the set of location coordinates was collectedrelative to the other collected sets of location coordinates and with arespective timestamp reflecting the time at which each set of locationcoordinates was collected (block 1406). The stored information may thenbe used to determine a room associated with the location informationcollected at block 1402 (block 1408). For example, the room may bedetermined by inputting the stored information into a method fordetermining or inferring if two sets of sequentially collected locationcoordinates accurately reflect the actual position of the PPM 104 orinstead reflect the position of the PPM 104 offset by a precision errorassociated with the location equipment installed in the PPM 104.

An example method shown by the flow diagram of FIG. 14B may be used todetermine or infer the accuracy of the location information byidentifying a set of location coordinates of interest. Initially, thecounting variable n is set equal to a starting index value and a lastcoordinate variable n_(last) equal to a last index value (block 1432).For example, if one thousand location coordinates are collected, thesecond half of the location coordinates may be analyzed by setting thecounting variable n equal to the index value five hundred and the lastcoordinate variable n_(last) equal to the index value one thousand.Next, the rooms associated with the n-th set of location coordinates andthe set of location coordinates n+1, are identified (block 1434) using,for example, the look-up table described above, and the rooms are thencompared (block 1436). If the comparison indicates that the rooms arethe same (i.e., room_(n)=room_(n+1)) then the audience member 106 isassumed to have remained in the same room between a time T_(n) at whichthe n-th set of location coordinates was collected and a time T_(n+1) atwhich the n+1 set of location coordinates was collected. In addition,the rooms identified for each set of location coordinates are assumed toaccurately reflect the location of the audience member 106 carrying thePPM 104. If the rooms are the same, an accuracy flag, or any othervariable, is associated with the corresponding set of locationcoordinates and set to indicate that the data is accurate (block 1438).

The counting variable n is then compared to the last coordinate variablen_(last) (block 1440) to determine if all of the location coordinateshave been analyzed. If all of the location coordinates have not beenanalyzed (e.g., n≠n_(last)), the counting variable n is incremented byone (i.e., n=n+1) (block 1441) and the process analyzes the nextsequentially collected set of location coordinates by repeating theprocessing described in connection with blocks 1434, 1436, 1438, and1440. However, if the all of the location coordinates have been analyzed(e.g., n=n_(last)), the process is ended.

If at block 1436 the rooms are different (i.e., room n≠room n+1), thenthe wall 119 separating the two rooms is identified as an interveningwall (block 1442) using, for example, a look-up table that includesentries identifying each set of adjacent rooms and the locationcoordinates associated with the wall (e.g., the wall 119) disposedbetween each set of adjacent rooms (e.g., the rooms 115 a and 115 c).

After the wall 119 separating the two rooms 115 a and 115 c isidentified, the two sets of location coordinates (X_(n), Y_(n)) and(X_(n+1), Y_(n+1)) are used in combination with a line equation y=Mx+bto determine a line (e.g., one of the lines 162 and 164 of FIG. 1B)extending between the two sets of coordinates (block 1444). The lineequation is used to determine whether any of the coordinates associatedwith the wall 119 reside on the line extending between the two sets ofcoordinates. Any of a number of known algebraic methods may be used todetermine whether the wall 119 intersects the line y=Mx+b, including forexample, any method used to determine whether any of the sets ofcoordinates defining the location of the wall 119 are valid solutions tothe line equation y=Mx+b (block 1446). The operation of block 1446 maybe performed by, for example, iteratively inserting each of the sets oflocation coordinates that define the location of the wall 119 into theequation y=Mx+b until a valid solution is identified. If none of thesets of coordinates of the wall 119 reside on the line extending betweenthe two sets of location coordinates (X_(n), Y_(n)) and (X_(n+1),Y_(n+1)), then the line passes through a doorway (e.g., the doorway 166of FIG. 1B) as illustrated by the line 164 of FIG. 1B. As a result, theprocess infers that the audience member 106 likely walked through thedoorway 166 providing passage between the two rooms 115 a and 115 c. Asa result, the two sequentially obtained sets of location coordinates(X_(n), Y_(n)) and (X_(n+1), Y_(n+1)) are treated as accuratelyreflecting the location of the audience member 106 such that any mediamonitoring information associated with these location coordinates (i.e.,collected at or at about the same time as the location information) arecredited in accordance with the proximity (or lack thereof) of any mediadelivery devices at those locations. Because the data is determined orinferred to be accurate, an accuracy flag is set to a value of 1 (block1438) that may be stored together with the location information orlocation coordinates in a memory. The accuracy flag may then be used byany subsequent processes used for crediting (or not) viewed media.

If it is determined at block 1446 that any of the coordinates of thewall 119 reside on the line, y=Mx+b, then the line passes through thewall 119 as illustrated by the line 162 of FIG. 1B. As a result, theprocess infers that one of the sequentially collected sets of locationcoordinates may be erroneous because the shortest distance between thetwo sequentially collected set of location coordinates (i.e., a straightline) suggests a path of travel through an intervening wall (e.g., thewall 119), an event that is not likely (barring a construction projectin which the wall has been removed or impaired in some way). Thus, thepositioning of the sequential sets of location coordinates relative tothe intervening wall 119 causes the accuracy of the sets of locationcoordinates to be considered suspect and thereby causes a suspect flagto be set (block 1448). The suspect flag may be used by any subsequentprocesses for crediting (or not) media as having been viewed or thesuspect flag may cause the initiation of a process for furtherevaluation of the sequentially collected sets of location coordinates.After the suspect flag is set at block 1448, control is passed back toblock 1440.

Another example method for analyzing or evaluating the sequentiallycollected location coordinates is shown in the flow diagram of FIG. 14C.The example method of FIG. 14C may involve, for example, determiningwhether travel from the first set of location coordinates to the secondset of location coordinates is possible in the duration of time elapsingbetween the collection of the sequential sets of location coordinatesassuming a path of travel (e.g., the path line 168 of FIG. 1B) through adoorway (e.g., the doorway 170 of FIG. 1B) disposed in the interveningwall 119 (FIG. 1B). The additional processing used to perform thisevaluation begins after two sequentially collected sets of locationcoordinates indicating a room change have been detected.

Initially, the counting variable n is set equal to a starting value andthe last coordinate variable n_(last) equal to a last value (block1450). Two sets of sequentially collected location coordinates (e.g.,(X_(n), Y_(n)) and (X_(n+1), Y_(n+1))) are then retrieved and examined(block 1451) to determine if each of the two sets correspond to adifferent room. It is then determined if the examination or analysis atblock 1451 indicate that the two sequentially collected sets of locationcoordinates each correspond to a different room (block 1452), therebyindicating that a room change has been detected. If the two sequentiallycollected sets of location coordinates do not correspond to differentrooms, then control is passed back to block 1452 where the next two setsof sequentially collected location coordinates (e.g., (X_(n+1), Y_(n+1))and (X_(n+2), Y_(n+2))) are retrieved and examined. However, if it isdetermined at block 1452 that two sets of sequentially collectedlocation coordinates correspond to different rooms (e.g., the rooms 115b and 115 c of FIG. 1B), then the elapsed time between the collection ofthe sets of location coordinates (X_(n), Y_(n)) and (X_(n+1), Y_(n+1))is determined by determining the time elapsed between the timestampsassociated with each (e.g., T_(elapsed)=T_(n+1)-T_(n)) (block 1454).

Next, the distance of travel between the first and second sets oflocation coordinates is calculated assuming a path of travel (e.g., thepath line 168 of FIG. 1B) through the doorway 170 providing passagebetween the first and second rooms 115 b and 115 c (block 1456). Thedistance of travel (D_(total)) may be calculated by adding the distancefrom the first set of location coordinates (X_(n), Y_(n)) to the centerof the doorway 170 (D_(XnYn to center)) to the distance from the centerof the doorway 170 to the second set of location coordinates(D_(center to Xn+1Yn+1)). An estimated rate of travel (R) may then bedetermined based on the time elapsed (T_(elapsed)) and the totaldistance (D_(total)) (block 1458). For example, the total distance(D_(total)) may be divided by the time elapsed (T_(elapsed)) to obtainthe estimated rate of travel (R). The rate of travel (R) may then becompared to a predefined, maximum expected rate of travel within thehousehold (R_(max)) (block 1460). The predefined, maximum expected rateof travel may vary in accordance with the mobility characteristics ofthe inhabitants of the household 102.

If it is determined at block 1460 that the estimated rate of travel (R)exceeds a predetermined, maximum expected rate of travel (R_(max))within the household 102, then an inaccuracy flag for the n+1 locationcoordinate (X_(n+1), Y_(n+1)) may be set to indicate that the n+1location coordinate is inaccurate or erroneous (block 1462) because itis unlikely that the audience member 106 traveled between the first andsecond sets of location coordinates within the elapsed time(T_(elapsed)). As described above, sets of location coordinates that areidentified as inaccurate or suspect are used to inform the creditingprocess, to prevent or limit inaccurate crediting.

If, instead, it is determined at block 1460 that the estimated rate oftravel (R) is not greater than the predefined, maximum expected rate oftravel within the household, then an accuracy flag for the n+1 locationcoordinate (X_(n+1), Y_(n+1)) may be set to indicate that the n+1location coordinate is accurate (block 1464). As described above, setsof location coordinates that are identified as accurate are used by thesystem to credit any media exposure occurring at the times at which thesets of location coordinates were collected.

The counting variable n is then compared to the last coordinate variablen_(last) (block 1466) to determine if all of the location coordinateshave been analyzed. If all of the location coordinates have not beenanalyzed, the counting variable n is incremented by one (i.e., n=n+1)(block 1468) and control is passed back to block 1451. However, if theall of the location coordinates have been analyzed (e.g., n=n_(last)),the process is ended.

An example method shown in FIG. 14D may be implemented by analyzing orprocessing a plurality of neighboring sets of location coordinates in acollective manner to identify a path of travel of the audience member106. The resulting information may be used to either supplant or supportthe conclusions reached about the accuracy of the collected data formedusing the location by location comparison/analysis described inconnection with FIGS. 14A-14C. For example, after a room change has beendetected, the example method of FIG. 14D may be used to process locationcoordinates collectively to identify the movement of the audience member106 using several sequentially collected sets of location coordinates.The number of sets of location coordinates used to identify the movementof the audience member 106 is preferably a sufficient number todetermine whether the audience member 106 is moving in a particulardirection. Identifying movement in a particular direction, in turn,requires that the movement of the audience member 106 be tracked for asufficient period of time.

The period of time sufficient to track movement in a particulardirection will vary depending on the frequency at which the PPM 104collects location information and the anticipated average rate ofmovement expected of the audience member 106. For example, if the PPM104 collects location information every second, then six suchcollections can be used to identify the movement of the audience member106 over a sufficient amount of time (e.g., six seconds) for theaudience member 106 to traverse a small room. If, instead, the PPM 104collects location information six times per second, then six suchcollections of location information can be used to reflect the movementof the audience member 106 over one second of time. However, one secondmay be an insufficient amount of time for an average person to havemoved a large enough distance to be able to identify any particulardirection of movement.

For purposes of clarity in describing the example method of FIG. 14D,assume that the PPM 104 collects location information at a rate of onceper second and that six seconds is a sufficient length of time for anaverage person to traverse across, or halfway across, an average sizedroom. Initially, the counting variable n is set equal to a startingvalue and a last coordinate variable n_(last) equal to a last value(block 1471). For example, the counting variable n may be set to anindex value corresponding to a first location coordinate to beretrieved. The last coordinate value n_(last) may be set to an indexvalue equal to the last index value to which the counting variable nshould be equal when the example method of FIG. 14D has analyzed all ofthe desired location coordinates. For example, if groups of six locationcoordinates are to be analyzed at a time and there are one thousand(e.g., 1-1000) location coordinates to be analyzed, the last coordinatevalue n_(last) should be set equal to one thousand minus five (e.g.,n_(last)=1000−5).

A set of location coordinates (e.g., (X_(n), Y_(n)) and (X_(n+1),Y_(n+1))) are then retrieved and examined (block 1472) to determine if aroom change has possibly occurred. It is then determined if theexamination or analysis of block 1472 indicates that a room change froma first room (e.g., the room 115 b of FIGS. 1A and 1B) to a second room(e.g., the room 115 c of FIGS. 1A and 1B) is detected (block 1474). If aroom change is not detected, control is passed back to block 1472. If aroom change is detected, a group (e.g., six sets) of locationcoordinates (e.g., (X_(n+2), Y_(n+2)) through (X_(n+7), Y_(n+7)))collected immediately subsequent to the detection of the room change arethen analyzed to determine whether they indicate a particular directionand path of travel or motion (block 1476). It is then determined whetherthat particular direction of travel or motion confirms that a roomchange is possible and/or likely occurred (block 1478).

If the six sets of location coordinates indicate that the audiencemember 106 remained in the room 115 c after detecting the room change(e.g., room change from the first room 115 b to the second room 115 c)and further indicate that the audience member 106 moved successivelyfarther away from the first room 115 b, then the audience member 106 isassumed to have actually moved from the first room 115 b into the secondroom 115 c. In this case, the occurrence of a room change is confirmed(block 1480) by, for example, setting a room change flag or settingaccuracy flags for each of the sets of coordinates to indicate that theroom change may be regarded as accurately reflecting the location of theaudience member 106.

If the six sets fail to indicate a particular direction of travel ormovement that proceeds successively farther away from the first room 115b, and instead indicate a path of travel that includes several movementsover short distances in different directions, then additional processingmay occur in an attempt to determine whether the audience member 106actually moved between rooms. For example, the room associated with eachof six subsequently collected sets of location coordinates may beidentified. Specifically, six subsequent location coordinates may becollected (block 1482) and analyzed to determine the room with which thesix subsequently collected location coordinates are associated. It isthen determined the six sets of location coordinates are disposed in thesecond room 115 c (block 1484). If it is determined that the six sets oflocation coordinates are disposed in the second room 115 c, control ispassed to block 1480 where it is confirmed that the detected movementbetween the rooms 115 b and 115 c is reflected by the locationcoordinates and may be treated as having actually occurred.

If the six sets of location coordinates are not within the second room115 c, it is determined if the six sets of location coordinates are alldisposed in the first room 115 b (block 1486). If the six sets oflocation coordinates are within the first room 115 b, then the detectedmovement into the second room 115 c may be treated as anomalous and maybe disregarded (block 1488). If, instead, the six sets of locationcoordinates indicate that the audience member 106 was moving back andforth between the first and second rooms 115 b and 115 c, then the nextsix sets of sequentially collected location coordinates may be analyzedto determine whether a direction of movement can be discerned by passingcontrol from block 1486 to block 1476.

The counting variable n is then compared to the last coordinate variablen_(last) (block 1490) to determine if all of the location coordinateshave been analyzed. If all of the location coordinates have not beenanalyzed (e.g., n≠n_(last)), the counting variable n is incremented byone (i.e., n=n+1) (block 1492) and control is passed back to block 1472.However, if all of the location coordinates have been analyzed (e.g.,n=n_(last)), the process is ended.

Alternatively, if the limitations of the accuracy of the locationequipment installed in the PPM 104 are known, an example method of FIG.14E may be used to treat, as suspect, all sets of location coordinatesthat indicate that the audience member 106 is located within a distance(e.g., the boundary zones 160 a-160 c of FIG. 1B) from any wall in thehome (e.g., the household 102 of FIGS. 1A and 1B) that is less than thelimits of accuracy of the equipment (e.g., the PPM 104 and/or thelocation information systems of FIG. 1A). Initially, locationinformation is collected (block 1492). The location equipment having anaccuracy of +/−six inches may be used to identify sets of locationcoordinates that are positioned within six inches of any wall in thehousehold 102 and tag those location coordinates as suspect (block1494). For example, a set of ten subsequently collected sets of locationcoordinates all positioned within six inches of a wall (e.g., within oneof the boundary zones 160 a-160 c) located in a first room are labeledas suspect.

The suspect data may then be analyzed in light of location datacollected before or subsequent to the suspect data (block 1496). Forexample, the ten location coordinates collected before and after thesuspect set of location coordinates may be used to identify a path oftravel taken by the audience member 106 before and after entering theregion of error represented by the ten sets of location coordinateslabeled as suspect.

The paths of travel may then be used to draw conclusions about suspectsets of location coordinates (block 1498). For example, if the path oftravel preceding the suspect coordinates indicate that the audiencemember 106 entered the first room and the path of travel subsequent tothe collection of the suspect coordinates indicates that the audiencemember 106 left the first room, then the process may conclude that thesuspect points shall be credited as though the audience member 106 werelocated in the first room. In contrast, if the path of travel precedingthe suspect coordinates labeled as suspect indicate that the audiencemember 106 entered a second room and the subsequently collected set oflocation coordinates indicate that the audience member left the secondroom, the process may conclude that the suspect points shall be creditedas though the audience member 106 were located in the second room. If,instead, the location coordinates collected after the suspect locationcoordinates are also suspect because they are located within six inchesof a wall (e.g., within the boundary zones 160 a-160 c) in the home,then the PPM 104 may be configured to reiteratively examine each of thenext, sequentially collected location coordinates until a set oflocation coordinates representing a location positioned farther than sixinches outside of the wall (e.g., outside of the boundary zones 160a-160 c) is identified. The preceding and subsequent paths of travel maybe used to draw a variety of conclusions about the suspect locationdata, depending on any number of factors including, the characteristicsof the inhabitants of the household, the rooms in which movement isbeing detected, the placement of furniture within the rooms in whichmovement is detected, etc.

FIG. 15 is a flow diagram of another example method that may be used tomanage spillover. In particular, the example method involves determiningthe spatial location of the PPM 104 (FIGS. 1 and 2) relative to any oneof the media delivery centers 112 (FIG. 1A) by correlating time delaysbetween received audio codes and received RF codes. In general, an RFtransmitter is placed near, adjacent, or on one or more of the mediadelivery centers 112. The RF transmitter may be implemented using thePPM interface 308 (FIG. 3) of the base unit 114 (FIGS. 1 and 3) and thebase unit 114 may be placed near, adjacent, or on the media deliverycenter 112. The base unit 114 may then be communicatively coupled to amedia delivery device (e.g., a television) of the media delivery center112 via, for example, the audio/video interface 316 to receive audioinformation from the media delivery center 112. Alternatively, the baseunit 114 may be configured to receive audio information signals fromspeakers of the media delivery center 112 via the microphone 320 (FIG.3).

The base unit 114 may convert the received audio information (i.e., theaudio information received via the audio/video interface 316 and/or themicrophone 320) into an AM modulated RF signal (block 1502) and transmitor broadcast the AM modulated RF signal via the PPM interface 308 (block1504). The AM modulated RF signal is transmitted at substantially thespeed of light. While the base unit 114 obtains the audio informationfrom the media delivery center 112, the media delivery center 112 alsobroadcasts an identical or corresponding audio information signal viaspeakers to the surrounding area (block 1506). When the PPM 104 is inthe vicinity of the base unit 114, the PPM 104 detects, receives, orotherwise obtains the AM-modulated RF signal and extracts the audioinformation (block 1508). The PPM 104 may then obtain the audioinformation signal that was broadcast by the media delivery center 112(block 1510) via the audio sensor 218 (FIG. 2). However, because theaudio signals transmitted by the speakers to the PPM 104 travel at thespeed of sound and the AM modulated RF signal transmitted by the baseunit 114 to the PPM 104 travels at the speed of light, there is a delaytime between receipt of the AM modulated RF signal and receipt of thecorresponding audio signal at the PPM 104.

The difference between the times at which the AM modulated RF signal andaudio information signal are received may be used to determine thedistance by which the PPM 104 is separated from the media deliverycenter 112. More specifically, after obtaining the audio information viathe audio sensor 218 and via the AM modulated RF signal, a correlationcan be performed between the two audio information signals to determinea delay time T (block 1512). The delay time T may then be multiplied bythe speed of sound (e.g., about 1000 ft/sec) (block 1514) to determinethe distance by which the PPM 104 is separated from the media deliverycenter 112. The distance information may then be used in combinationwith the example grid marker layouts illustrated in FIGS. 4 through 7 todetermine whether the PPM 104 is located in the same room as the mediadelivery center 112 (block 1516).

FIG. 16 is a flow diagram of another example method that may be used tomanage spillover. In particular, instead of identifying a distance atwhich the PPM 104 (FIGS. 1A-1C and 2) is located from the media deliverycenter 112 (FIG. 1A), the system may be configured to calculate thelocation (e.g., the precise location) of the PPM 104 within the room orhousehold (e.g., the household 102). Such a system includes twotransmitters (e.g., two of the base units 114) disposed within the sameroom. For example, one of the base units 114 may be disposed on or nearthe media delivery center (e.g., one of the media delivery centers 112of FIG. 1A) and the other one of the base units 114 may be disposed at adifferent location within the same room.

The base units 114 disposed within the same room are both configured toemit RF signals and/or optical signals (e.g., electromagnetic radiationsignals, Wi-Fi® signals, radio waves, or infrared radiation signals)via, for example, the RF location interface 306 (FIG. 3) and/or the PPMinterface 308 (FIG. 3) and emit audio signals via, for example, thespeaker 318 (FIG. 3). The audio signals may be inaudible to the humanear so as to limit any annoyance to household members. The audio signalsand the RF signals emitted by each of the base units 114 are uniquelyassociated with the base units 114 from which the signals originated.For example, each of the RF signals and audio signals may have codesembedded therein that identify from which of the base units 114 each ofthe signals was emitted.

Initially, each of the base units 114 generates an RF signal and anaudio signal (block 1602). The base units 114 may generate timestamps(e.g., the timestamps T1 and T2 described above in connection with FIG.15) and embed the timestamps into the RF signals and the audio signals.The timestamps represent the time at which the RF signals and the audiosignals are emitted by the base units 114. The base units 114 then emitthe RF signals and the audio signals generated at block 1602 (block1604). Each of the base units 114 may emit the RF signal and the audiosignal at (or about) substantially the same time. To avoid overlap, eachof the base units 114 may emit an RF signal and an audio signal at atime that is offset from the time at which the other one of the baseunits 114 emits an RF signal and an audio signal.

The PPM 104 then detects the RF signals and the audio signals (block1606). The PPM 104 may generate a timestamp (e.g., the timestamps T3 andT4 described above in connection with FIG. 15) for each received RFsignal and audio signal (block 1608). The timestamps may be used torepresent the time at which each RF signal and audio signal was receivedby the PPM 104. The PPM 104 then determines which base unit 114 emittedeach of the RF signals and audio signals (block 1610). The PPM 104 isprogrammed with information (e.g., base unit identification informationin a look-up table or database) that is used to identify the base unit114 from which each signal originated.

The PPM 104 then calculates the propagation delay or time delay of eachof the RF signals (block 1612). For example, the PPM 104 may subtractthe timestamp corresponding to the time at which the PPM 104 received anRF signal from the timestamp corresponding to the time at which one ofthe base units 114 emitted the RF signal. The PPM 104 then determinesthe distance between the PPM 104 and each of the base units 114 (block1614). Specifically, the PPM 104 multiplies each of the time delays bythe speed of sound to determine the distance between the PPM 104 and theoriginating base units 114. This calculation assumes that the RF signal(traveling at or near the speed of light) is essentially received by thePPM 104 instantaneously such that the time delay between the receipt ofthe RF signal and the audio signal represents the time taken by theaudio signal to travel to the PPM 104.

After determining a first distance between the PPM 104 and a first oneof the base units 114 and a second distance between the PPM 104 and asecond one of the base units 114, these distances can be combined withinformation about the location of the first and second base units 114within the household 102 (FIG. 1A) to identify the location of the PPM104 within the household 102 (block 1616). The location of the PPM 104within the household 102 may be determined using the first and seconddistances in combination with, for example, a technique that issubstantially similar or identical to the technique described above inconnection with FIGS. 1C and 13B. Specifically, the first and seconddistances and the location of each of the base units 114 within thehousehold 102 can be processed using a technique that is substantiallysimilar to a triangulation technique to identify the location of the PPM104 within the household 102.

The base units 114 configured to generate an audio signal and an RFsignal may be adapted to generate such signals in a manner that isdependent on or in some way triggered by the emission of an audio signalby the media delivery center 112 (FIG. 1A) or may instead be adapted togenerate such signals at periodic intervals or non-periodic intervalsthat are in no way connected to or triggered by audio signals emitted bythe media delivery center 112.

FIG. 17 is a block diagram of an example processor system 1710 that maybe used to implement the apparatus and methods described herein. Asshown in FIG. 17, the processor system 1710 includes a processor 1712that is coupled to an interconnection bus 1714. The processor 1712includes a register set or register space 1716, which is depicted inFIG. 17 as being entirely on-chip, but which could alternatively belocated entirely or partially off-chip and directly coupled to theprocessor 1712 via dedicated electrical connections and/or via theinterconnection bus 1714. The processor 1712 may be any suitableprocessor, processing unit or microprocessor. Although not shown in FIG.17, the system 1710 may be a multi-processor system and, thus, mayinclude one or more additional processors that are identical or similarto the processor 1712 and that are communicatively coupled to theinterconnection bus 1714.

The processor 1712 of FIG. 17 is coupled to a chipset 1718, whichincludes a memory controller 1720 and an input/output (I/O) controller1722. As is well known, a chipset typically provides I/O and memorymanagement functions as well as a plurality of general purpose and/orspecial purpose registers, timers, etc. that are accessible or used byone or more processors coupled to the chipset 1718. The memorycontroller 1720 performs functions that enable the processor 1712 (orprocessors if there are multiple processors) to access a system memory1724 and a mass storage memory 1725.

The system memory 1724 may include any desired type of volatile and/ornon-volatile memory such as, for example, static random access memory(SRAM), dynamic random access memory (DRAM), flash memory, read-onlymemory (ROM), etc. The mass storage memory 1725 may include any desiredtype of mass storage device including hard disk drives, optical drives,tape storage devices, etc.

The I/O controller 1722 performs functions that enable the processor1712 to communicate with peripheral input/output (I/O) devices 1726 and1728 and a network interface 1730 via an I/O bus 1732. The I/O devices1726 and 1728 may be any desired type of I/O device such as, forexample, a keyboard, a video display or monitor, a mouse, etc. Thenetwork interface 1730 is communicatively coupled to the network 124 andmay be, for example, an Ethernet device, an asynchronous transfer mode(ATM) device, an 802.11 device, a DSL modem, a cable modem, a cellularmodem, etc. that enables the processor system 1710 to communicate withanother processor system.

While the memory controller 1720 and the I/O controller 1722 aredepicted in FIG. 17 as separate functional blocks within the chipset1718, the functions performed by these blocks may be integrated within asingle semiconductor circuit or may be implemented using two or moreseparate integrated circuits.

FIG. 18 is an example location monitoring system 1800 (i.e., themonitoring system 1800) that may be used to implement the methods andapparatus described herein. The monitoring system 1800 may be configuredto work with the example PPM 104 (FIGS. 1A-2) to generate locationinformation associated with the location of a person (e.g., the audiencemember 106 of FIGS. 1A-1C) within a household (e.g., the household 102of FIGS. 1A-1C or the household 2200 of FIG. 22) as described below inconnection with the example methods of FIGS. 23 and 24. The monitoringsystem 1800 or another processing system (e.g., the home processingsystem 120 or the server 126 of FIG. 1) may then use the locationinformation in combination with media monitoring information collectedby the PPM 104 to determine the media to which the audience member 106was exposed as described below in connection with the example methods ofFIGS. 23 and 25A-25B.

The monitoring system 1800 may be implemented using ultrasoundtechnologies for detecting the location of the PPM 104 within thehousehold 2200. In particular, as the PPM 104 moves from room to room,the monitoring system 1800 may obtain ultrasound signals emitted by thePPM 104, extract a PPM ID from the ultrasound signals and store the PPMID with corresponding location identification codes (i.e., locationID's) for subsequent analyses.

As shown in FIG. 18, the monitoring system 1800 includes two base sensorunits 1802 a and 1802 b communicatively coupled to a data collectionunit 1804 via a network hub 1806. The base sensor units 1802 a-b arecommunicatively coupled to a plurality of satellite sensor units 1808.The base sensor units 1802 a-b and the satellites sensor units 1808 mayinclude microphones or transducers (e.g., the microphone 320 of FIG. 3)that enable the sensor units 1802 a-b and 1808 to detect PPM ID signals(e.g., PPM beacon signals) emitted by PPM's using acoustic frequenciessuch as, for example, ultrasound frequencies. Each of the base sensorunits 1802 a-b may have eight data acquisition channels numbered zerothrough seven. The microphone or transducer of each of the base sensorunits 1802 a-b may be coupled to data acquisition channel zero. Each ofthe satellite sensor units 1808 may be coupled to a respective one ofthe data acquisition channels one through seven of the base sensor units1802 a-b.

The base sensor units 1802 a-b may be communicatively coupled to thedata collection unit 1804 using any suitable networking standard (e.g.,Ethernet, Token Ring, etc.). Although the base sensor units 1802 a-b areshown as being coupled via wires to the data collection unit 1804, in analternative implementation, the base sensor units 1802 a-b may becommunicatively coupled to the data collection facility 1804 using awireless communication protocol. Each of the base sensor units 1802 a-bmay be assigned a unique IP address that enables the each of the basesensor units 1802 a-b to communicate with the central data collectionunit 1804. The data collection unit 1804 may store the locationinformation received from the base sensor units 1802 a-b in a databaseand/or communicate the location information to, for example, the centralfacility 122 (FIG. 1A).

The base sensor units 1802 a-b may be powered by an alternating current(AC) source (e.g., a wall outlet) or a direct current (DC) source (e.g.,an AC-DC converter plugged into a wall outlet). The satellite sensorunits 1808 may be powered by the base sensor units 1802 a-b.Specifically, a cable used to couple a satellite sensor unit 1808 to oneof the base sensor units 1802 a-b may include a data communication linkthat is coupled to one of the data acquisition channels zero throughseven and a power link that is coupled to a power supply of the one ofthe base sensor units 1802 a-b. As described below, the sensor units1802 a-b and 1808 may be placed throughout the household 2200 to detectthe location of the PPM 104 as the PPM 104 moves from room to room. Thebase sensor units 1802 a-b may communicate to the data collection unit1804 any PPM information acquired by the satellite sensor units 1808 orthe base sensor units 1802 a-b. In some implementations, the datacollection unit 1804 may be integral with the home processing system120.

The sensor units 1802 a-b and 1808 may be placed throughout thehousehold 2200 and assigned a location ID corresponding to the room inwhich it is located. In some implementations or household floor plans,two or more of the sensor units 1802 a-b and 1808 may be located in eachroom. The sensor units 1802 a-b and 1808 may be placed within rooms asdescribed below in connection with FIGS. 19-22 to substantially reduceor eliminate signal spillover effects. In this manner, the examplesystem 1800 may be used to accurately determine in which room a person(e.g., the audience member 106 of FIG. 1) is located.

The example monitoring system 1800 may be used to determine the locationof the audience member 106 within the household 2200 as the PPM 104 ismoved from room to room. For example, as the PPM 104 emits PPM IDsignals encoded with a PPM identification code (i.e., a PPM ID), thesensor units 1802 a-b and 1808 may detect the PPM signals and extractthe PPM ID from the PPM ID signals. After a sensor unit extracts the PPMID, the sensor unit may generate location information by tagging the PPMID with a timestamp and a location ID corresponding to the room of thehousehold 2200 in which the sensor unit is located. The data collectionunit 1804 or another processing system (e.g., the home processing system120 or the server 126) may later use the location information todetermine the room or rooms within which the audience member 106 waslocated. As described in greater detail below in connection with theexample methods of FIGS. 23-25B, the location information may be used incombination with media monitoring information collected by the PPM 104to determine the rooms in which the audience member 106 was locatedwhile consuming media.

FIGS. 19-21 are example sensor placement configurations that may be usedto place the sensor units 1802 a-b and 1808 of FIG. 18 throughout ahousehold (e.g., the household 2200 of FIG. 22). In particular, theplacement configurations of FIGS. 19-21 substantially eliminate orreduce spillover effects when the PPM 104 is moved from room to room inthe household 2200 and, thus, enable the monitoring system 1800 (FIG.18) to generate relatively accurate location information for the PPM104. The sensor units of FIGS. 19-21 are substantially similar oridentical to the sensor units 1802 a-b and 1808 of FIG. 18. The sensorunits of FIGS. 19-21 may be placed in back-to-back configurations, neardoor ways, on opposing sides of first floor and second floor boundaries,etc. so that the strongest PPM signals detected by each of the sensorunits 1802 a-b and 1808 correspond to a PPM located in the respectiveroom of each of the sensors 1802 a-b and 1808.

FIG. 19 is an example sensor configuration that may be used to installsensor units in first and second rooms 1902 and 1904 that are notseparated by a physical wall, but that are instead open to one another.A first set of sensor units 1906 a-c are mounted to the ceiling of thefirst room 1902 facing the first room 1902. A second set of sensor units1908 a-c are mounted to the ceiling of the second room 1404 in aback-to-back configuration with the first set of sensor units 1906 a-cand configured to face the second room 1904. When the PPM 104 is locatedwithin the first room 1904, the back-to-back configuration shown in FIG.19 enables the first sensor units 1906 a-c to detect relatively strongerPPM signals and the second sensor units 1908 a-c to detect no PPMsignals or substantially weaker PPM signals. In a similar manner, whenthe PPM 104 is located in the second room 1906, the second sensor units1908 a-c may detect relatively stronger PPM signals and the first sensorunits 1906 a-c may detect no PPM signals or relatively weaker PPMsignals.

FIG. 20 is an example sensor configuration that may be used to install asensor unit 2002 above a door 2004 of a room. The sensor unit 2002 ismounted to a wall above the door 2004 to enable the sensor unit 2002 todetect relatively strong PPM signals when the PPM 104 (FIGS. 1A-2) ismoved into the room and to detect no PPM signals or relatively weak PPMsignals from the PPM 104 when the PPM 104 is moved out of the room.

FIG. 21 is an example sensor configuration that may be used to installsensor units in adjacent upper and lower floors. In a multi-level homeconfiguration as shown in FIG. 21, location sensor units may be placedin substantially opposing directions. In this manner, when the PPM 104is located on the upper floor, upper floor sensor units 2102 a-b detectrelatively stronger PPM signals and lower floor sensor units 2104 a-b todetect no PPM signals or relatively weak PPM signals from the PPM 104.

FIG. 22 is a floor plan view of the example household 2200 illustratingan example placement configuration for the sensor units 1802 a-b and1808 of FIG. 18. The example monitoring system 1800 of FIG. 18 may beinstalled in the example household 2200 to collect location informationassociated with the rooms of the household 2200 in which a person (e.g.,the audience member 106 of FIGS. 1A-1C) performs daily activities suchas media consumption. Specifically, sensor units shown in FIG. 22 andindicated generally by reference numerals 2202 a-g may be placedthroughout the household 2200 using the placement configurationsdescribed above in connection with FIGS. 19-21 to substantially reduceor eliminate spillover effects associated with PPM ID signals thatspillover or leak from one room to another. The sensor units 2202 a-gare substantially similar or identical to the sensor units 1802 a-b and1808 of FIG. 18.

As shown in FIG. 22, a first sensor unit 2202 a and a second sensor unit2202 b are placed in the household 2200 to enable monitoring for PPMsignals in a kitchen 2204 and a dining room 2206. Third and fourthsensor units 2202 c-d are placed in the household 2200 to monitor asitting room 2208. Fifth and sixth sensor units 2202 e-f are placed inthe household 2200 to monitor an entertainment room 2210. A seventhsensor unit 2202 g is placed in the household 2200 to monitor a bedroom2212.

The first and second sensor units 2202 a-b may be placed on opposingsides of a wall above a door (e.g., the door 2004 of FIG. 20) separatingthe kitchen 2204 and the dining room 2206 as shown in FIG. 20, forexample. The first sensor unit 2202 a is positioned or configured todirect the PPM signal sensing capabilities (e.g., the signal sensing orpick up capabilities of a microphone) of the first sensor unit 2202 atoward the area of the kitchen 2204 as generally indicated by arrow2214. The second sensor unit 2202 b is positioned or configured todirect the PPM signal sensing capabilities of the second sensor unit2202 b toward the area of the dining room 2206 as generally indicated byarrow 2216. In this manner, PPM signals emitted by PPM's within thekitchen 2204 will be relatively stronger when detected by the firstsensor unit 2202 a than spillover PPM signals emitted by PPM's in thedining room 2206. Similarly, PPM signals emitted by PPM's within thedining room 2206 will be relatively stronger when detected by the secondsensor unit 2202 b than PPM signals emitted by PPM's in the kitchen 2204that spill over into the dining room 2206. As described below inconnection with the example method of FIG. 24, a sensor unit (e.g., oneof the sensors 2202 a-g) or a processing system (e.g., the datacollection unit 1804 of FIG. 18, the home unit 120 of FIG. 1A, theserver 126 of FIG. 1A, etc.) may differentiate between PPM signals thatcorrespond to PPM's located within their respective rooms from PPMsignals that correspond to PPM's located in other rooms based on signalstrength.

The sitting room 2208 and the entertainment room 2210 are not separatedby a wall or a door. Instead the sitting room 2208 and the entertainmentroom 2210 are open to one another. In this case the third and fourthsensor units 2202 c-d and the fifth and sixth sensor units 2202 e-f maybe arranged in back-to-back configurations as described above inconnection with FIG. 19. The third and fourth sensor units 2202 c-d arepositioned or configured to direct the PPM signal sensing capabilitiesof the third and fourth sensor units 2202 c-d toward the area of thesitting room 2208 as generally indicated by arrows 2218 and 2220. Thefifth and sixth sensor units 2202 e-f are positioned or configured todirect the PPM signal sensing capabilities of the fifth and sixth sensorunits 2202 e-f toward the area of the entertainment room 2210 asgenerally indicated by arrows 2222 and 2224. In this configuration, thesensor units 2202 c-f detect PPM signals emitted by PPM's located inrespective rooms as being relatively stronger than spillover PPM signalsemitted by PPM's in other rooms.

The seventh sensor unit 2202 g may be mounted to an upper wall of a doorway separating the bedroom 2212 from a hallway as shown in FIG. 20. Theseventh sensor unit 2202 g is positioned or configured to direct the PPMsignal sensing capabilities of the seventh sensor unit 2202 g toward thearea of the bedroom 2212 as generally indicated by arrows 2226.

FIGS. 23 through 25B are example methods that may be used to managemedia signal (e.g., audio code) spillover associated with an audiencemonitoring system (e.g., the example location monitoring system 1800 ofFIG. 18). The example methods may be implemented in software, hardware,and/or any combination thereof. For example, the example methods may beimplemented in software that is executed on the PPM 104 of FIGS. 1A-2,the base units 114 of FIGS. 1A and 3, the example monitoring system 1800of FIG. 18, the home processing system 120 of FIG. 1A, and/or at thecentral facility 122 of FIG. 1A. Although, the example methods aredescribed below as a particular sequence of operations, one or moreoperations may be rearranged, added, and/or removed to achieve the sameor similar results as those described herein.

FIG. 23 is an example method that may be used to collect, manage, andanalyze media monitoring information and location information associatedwith media consumption activities of an audience member (e.g., theaudience member 106 of FIG. 1A) using the example location monitoringsystem 1800 of FIG. 18. The example method of FIG. 23 may be implementedusing a sensor unit configuration or layout as described above inconnection with FIG. 22 or any other sensor unit layout.

Initially, the PPM 104 obtains a media signal (block 2302). For example,the PPM 104 may detect audio emitted by a media delivery center (e.g.,any of the media delivery centers 112 of FIG. 22). The PPM 104 thengenerates a timestamp associated with the time at which the PPM 104obtained the media signal (block 2304). The PPM 104 then obtains mediaidentification information (e.g., an audio code, an audio signature,etc.) from the media signal (block 2306). For example, the PPM 104 mayextract an ancillary audio code from the media signal or may generate anaudio signature based on the media signal.

The PPM 104 then generates a media monitoring information record bytagging the media identification information with the timestamp and aPPM ID corresponding to the PPM 104 and stores the media monitoringinformation record in a memory (e.g., the memory 204 of FIG. 2) (block2308). For example, the PPM 104 may generate media monitoringinformation by storing the media identification information in a mediaID database entry and storing the timestamp in a timestamp databaseentry and the PPM ID in a PPM ID database entry, both corresponding tothe media ID entry in which the PPM 104 stored the media identificationinformation. Alternatively, the PPM 104 may generate media monitoringinformation by concatenating the media ID signal, the timestamp, and thePPM ID and storing the media monitoring information in the memory 204.

The PPM 104 may then determine whether to communicate the mediamonitoring information to a central processing system (e.g., the homeprocessing system 120 of FIG. 1) (block 2310). For example, the PPM 104may be configured to communicate the stored media monitoring informationto the home processing system 120 at predetermined times or when the PPM104 has collected a certain amount of media monitoring information orwhen the memory 204 (FIG. 2) is full.

If the PPM 104 determines that it should communicate the mediamonitoring information to the home processing system 120, then the PPM104 communicates the media monitoring information to the home processingsystem 120 (block 2312). For example, the PPM 104 may communicate themedia monitoring information to the home processing system 120 using awired or wireless communication protocol via the communication interface206 (FIG. 2).

A location sensor unit (e.g., one of the sensor units 2202 a-g of FIG.22) may obtain a PPM ID signal and the example monitoring system 1800(FIG. 18) may generate location information records based on the PPM IDsignal (block 2314). For example, as the PPM 104 is moved between roomsof the household 2200 the PPM 104 periodically emits a PPM ID signalthat one or more of the sensor units 2202 a-g may detect. The locationsensor unit may then generate location information by extracting a PPMID from the PPM ID signal and tagging the PPM ID with a location ID ofthe room corresponding to the location sensor unit. The operation ofblock 2314 may be implemented as described below in connection with theexample method of FIG. 25 for generating location information. Asdescribed below in connection with the example method of FIG. 25, thelocation sensor unit may communicate the location information to thedata collection unit 1804 (FIG. 18) for subsequent analyses. Theoperation of block 2314 may be performed by the location sensor unit atsubstantially the same time as the PPM 104 performs the operations ofblocks 2302, 2304, 2306, 2308, 2310, and 2312 or at any other time.

The example monitoring system 1800 may then determine whether tocommunicate the location information via the data collection unit 1804to a central processing system (e.g., the home processing system 120 ofFIG. 1) (block 2316). For example, the data collection unit 1804 maycommunicate the location information at predetermined times or inresponse to a request by the home processing system 120.

If the example monitoring system 1800 determines not to communicate thelocation information to the home processing system 120, control isreturned to block 2302. However, if the example monitoring system 1800determines at block 2316 that it should communicate the locationinformation to the home processing system 120, then the data collectionunit 1804 locates all location information records (block 2318). Thedata collection unit 1804 then communicates all the location informationrecords to the home processing system 120 (block 2320). The homeprocessing system 120 may then analyze the location and media monitoringinformation (block 2322). The home processing system 120 may thencommunicate the analyses results and/or the location and mediamonitoring information to the central facility 122 (FIG. 1) (block2324). For example, the home processing system 120 may communicate theanalyses results and information records to the central facility 122according to a predetermined schedule (e.g., once per day at midnight).

FIG. 24 is an example method that may be implemented in combination withthe example method of FIG. 23 and used to generate location informationvia the example monitoring system 1800 of FIG. 18. The example method ofFIG. 24 may be implemented using location sensors (e.g., the sensorunits 2202 a-g) located throughout a household (e.g., the household 2200of FIG. 22) as described above in connection with FIG. 22. The examplemethod of FIG. 24 may be used to implement the operation of block 2314described above in connection with the example method of FIG. 23.

Initially, a location sensor unit (e.g., the location sensor unit 2202 aof FIG. 22) monitors for the presence of a PPM ID signal (block 2402).For example, the location sensor unit 2202 a may monitor for thepresence of a PPM ID signal using an ultrasonic microphone ortransducer. The location sensor unit 2202 a then determines if it hasdetected a PPM ID signal (block 2404). For example, the location sensorunit 2202 a may detect a PPM ID signal when the PPM 104 is moved intothe kitchen 2204 (FIG. 2). If the location sensor unit 2202 a does notdetect a PPM ID signal, control is returned to block 2402.

If the location sensor unit 2202 a detects a PPM ID signal, the locationsensor unit 2202 a may determine the signal power of the PPM ID signal(block 2406) by, for example, measuring the amplitude of the PPM IDsignal. The location sensor unit 2202 a may then generate a timestampassociated with the time at which the location sensor unit 2202 areceived the PPM ID signal (block 2408). The location sensor unit 2202 amay then extract a PPM ID from the PPM ID signal (block 2410). Thelocation sensor unit 2202 a then generates a location information recordby tagging the PPM ID with the signal power determined at block 2406,the timestamp generated at block 2408, and a location ID associated withthe room (e.g., the kitchen 2202 a) in which the location sensor unit2202 a is located (block 2412).

The location sensor unit 2202 a then communicates the locationinformation record generated at block 2412 to the data collection unit1804 (block 2414). The data collection unit 1804 obtains locationinformation records from all the location sensor units 2202 a-g (FIG.22) (block 2416). For example, the data collection unit 1804 may obtainlocation information records from the sensor units 2202 a-g in realtime. In other words, each of the location sensor units 2202 a-g maycommunicate a location information record to the data collection unit1804 immediately after it obtains a PPM ID signal and generates thelocation information record. The data collection unit 1806 thendetermines if the PPM ID signal received by the location sensor unit2202 a at block 2404 was detected by another one or more of the otherlocation sensor units 2202 b-g (block 2418). For example, the datacollection unit 1804 may compare the timestamp of the locationinformation record generated at block 2412 by the location sensor unit2202 a with timestamps of location information records generated byothers of the location sensor units 2202 b-g. The data collection unit1804 may select all location information records having a timestamp thatis substantially similar or identical (e.g., based on a particular timethreshold value) to the timestamp of the location information recordreceived from the location sensor unit 2202 a. The data collection unit1804 may then extract the PPM ID's from the selected locationinformation records and compare the PPM ID's to the PPM ID received fromthe location sensor unit 2202 a. The data collection unit 1804determines that at least one of the other location sensor units 2202 b-greceived the same PPM ID as the location sensor unit 2202 a received atblock 2404 if at least one of the other PPM ID's is equal to the PPM IDreceived from the location sensor unit 2202 a. In this case, the datacollection unit 1804 identifies and tags the location information recordhaving the strongest signal power (block 2420). For example, the datacollection unit 1804 may identify the location information record havingthe strongest signal power by comparing the signal power determined atblock 2406 with the signal powers of the other location informationrecords identified at block 2418. The data collection unit 1804 may tagthe location information record associated with the strongest signalpower by ranking it higher than all the other location informationrecords identified at block 2418, by placing it first in a list of thelocation information records, by discarding or disregarding all theother location information records, or by any other suitable manner.After tagging the location information records having the strongestsignal power or if the data collection unit determines at block 2418that none of the other location sensor units 2202 b-g detected the samePPM ID signal, the example monitoring system 1800 determines whether itshould continue to monitor for PPM ID signals (block 2422). If theexample monitoring system 1800 determines that it should continuemonitoring, then control is passed back to block 2402. Otherwise,control is returned to, for example, a calling function or process suchas the example method of FIG. 23.

FIGS. 25A-25B illustrate an example method that may be implemented incombination with the example method of FIG. 23 and used to analyzelocation and media monitoring information via a central processingsystem (e.g. home processing system 120 of FIG. 1A). In particular, theexample method of FIGS. 25A-25B may be used to implement the operationof block 2322 of FIG. 23. The example method is described below as aseries of operations executed or performed by the home processing system120. However, the operations of the example method may be executed orperformed by any other processing system such as, for example, theserver 126 (FIG. 1) or the data collection unit 1804 (FIG. 18).

Initially, the home processing system 120 obtains media monitoringinformation records and location information records (block 2502). Forexample, the home processing system 120 may obtain the media monitoringinformation records from the PPM 104 (FIGS. 1A-2) that are communicatedby the PPM 104 at the operation of block 2312 described above inconnection with FIG. 23. Additionally, the home processing system 120may obtain the location information records from the data collectionunit 1804 that are communicated by the data collection unit 1804 at theoperation of block 2320 (FIG. 23). The home processing system 120 maystore all of the media monitoring information and location informationrecords in a memory such as, for example, the mass storage memory 1725(FIG. 17).

The home processing system 120 may then sort the media monitoringinformation and location information records obtained at block 2502(block 2504). For example, the home processing system 120 may sort theinformation records based on timestamps and PPM ID's. The homeprocessing system 120 may generate a PPM ID data table for each PPM IDassociated with a particular household. The home processing system 120may sort the information records into corresponding PPM ID data tablesbased on the PPM ID's stored in the information records at block 2308(FIG. 23) and block 2412 (FIG. 24). Additionally, for each PPM ID datatable, the home processing system 120 may pair the media monitoringinformation records with corresponding location information recordsbased on substantially similar, identical, or otherwise correspondingtimestamps. The example methods of FIGS. 25A-25B are described withrespect to one of the PPM ID data tables. However, the informationrecords in all of the PPM ID data tables may be processed or analyzed ina substantially similar or identical manner.

The home processing system 120 obtains a first media monitoringinformation record and a first location information record (block 2506).For example, the home processing system 120 may obtain from the massstorage memory 1725 a first one of the media monitoring informationrecords and a first one of the location information records from a PPMID data table generated at block 2504. The home processing system 120then determines if valid media ID information exists in the mediamonitoring information record (block 2508). For example, if the PPM 104is configured to periodically generate a media monitoring informationrecord, during times when the PPM 104 is not be exposed to mediapresentations, the PPM 104 may generate a filler or a dummy mediamonitoring information record having no valid media ID information(e.g., an ancillary audio code, an audio signature, etc.). If the homeprocessing system 120 determines that valid media ID information doesnot exist in the media monitoring information record, then the homeprocessing system 120 may specify that the audience member 106 (FIG. 1)was not exposed to any media presentations or media information when theaudience member 106 was located in the room corresponding the locationinformation record retrieved at block 2506 (block 2510). For example,the home processing system 120 may tag the location information recordas not being associated with any media information and may store thatanalysis information in an analyses results database. The homeprocessing system 120 may then determine whether to obtain another setof media monitoring and location information records (block 2512). Ifthe home processing system 120 determines that it should obtain anotherset of information records, control is passed back to block 2502.Otherwise, control is returned to, for example, a calling function orprocess such as the example method of FIG. 23.

If at block 2508 the home processing system 120 determines that themedia monitoring information record includes valid media ID information(e.g., an ancillary audio code, an audio signature, etc.), then the homeprocessing system 120 extracts a location ID from the locationinformation record (block 2514). The home processing system 120 mayextract from the location information record the location ID that wastagged or added to the location information record at block 2412 of FIG.24. The home processing system 120 then determines if a media deliverydevice (e.g., one of the media delivery devices 112 of FIG. 22) islocated within the room corresponding to the location ID extracted atblock 2514 (block 2516). For example, the home processing system 120 mayhave a media delivery device look-up table or database stored in themass storage memory 1725 (FIG. 17) that includes a list of location ID'sand which of the location ID's are associated with the media deliverydevices 112. The home processing system 120 may use the media deliverydevice look-up table or database to determine which rooms of thehousehold 2200 include one of the media delivery devices 112. Thelook-up table or database may also include the type of media deliverydevice (e.g., radio, television, DVD player, CD player, etc.) that islocated within the rooms corresponding to the location ID's.

If the home processing system 120 determines at block 2516 that one ofthe media delivery devices 112 is located in the room corresponding tothe location ID, then the home processing system 120 tags the mediamonitoring information record as being associated with media that wasconsumed in the room corresponding to the location ID (block 2518). Forexample, the home processing system 120 may add a non-spillover code tothe media monitoring information record and/or the location informationrecord.

Otherwise, if the home processing system 120 determines at block 2516that one of the media delivery devices 112 is not located in the roomcorresponding to the location ID, then the home processing system 120may tag the media monitoring information record as spillover orotherwise specify that the media associated with the media monitoringinformation was spilled over to the room associated with the location ID(block 2520). For example, the home processing system 120 may add aspillover code to the media monitoring information record and/or thelocation information record.

After the home processing system 120 tags the information records asnon-spillover at block 2518 or as spillover at block 2520, the homeprocessing system 120 determines whether to obtain another set of mediamonitoring and location information records (block 2522). If the homeprocessing system 120 determines that it should obtain another set ofinformation records, control is passed back to block 2502. Otherwise,control is returned to, for example, a calling function or process suchas the example method of FIG. 23.

Although certain methods, apparatus, and articles of manufacture havebeen described herein, the scope of coverage of this patent is notlimited thereto. To the contrary, this patent covers all methods,apparatus, and articles of manufacture fairly falling within the scopeof the appended claims either literally or under the doctrine ofequivalents.

1. A method of detecting spillover to generate media monitoringinformation, comprising: receiving a first location signal and a secondlocation signal substantially simultaneously at a portable meteringdevice, wherein the first location signal is emitted via a first devicelocated at a first location and includes a first signal characteristicassociated with the first location, and wherein the second locationsignal is emitted via a second device located at a second location andincludes a second signal characteristic associated with the secondlocation; selecting the first location signal or the second locationsignal based on the first and second signal characteristics; andgenerating media monitoring information based on the selected signal. 2.A method as defined in claim 1, wherein the first device is adjacent toa first surface of a wall and the second device is adjacent to a secondsurface of the wall.
 3. (canceled)
 4. A method as defined in claim 1,wherein the first and second signal characteristics are associated withat least one of a signal strength, a signal frequency, or a locationcode.
 5. A method as defined in claim 1, wherein generating the mediamonitoring information comprises storing an audio code associated withmedia detected by the portable metering device while located in one ofthe first location or the second location.
 6. (canceled)
 7. A method asdefined in claim 1, wherein the first device is one of a first radiofrequency transmitter tower or a satellite and the second device is oneof a base unit located within an indoor location or a second radiofrequency transmitter located at an outdoor location.
 8. A method asdefined in claim 1, further comprising, when generating the mediamonitoring information based on the selected signal, identifying themedia monitoring information as being associated with a spilloversignal, the spillover signal being indicative of a media presentationpresented in a second room and detected by the portable metering devicelocated in a first room.
 9. A method as defined in claim 8, wherein theselected signal is indicative of the first room, and wherein the mediamonitoring information is identified as being associated with thespillover signal in response to determining that a media delivery deviceis not located in the first room indicated by the selected signal.
 10. Amethod as defined in claim 8, wherein the media monitoring informationbeing associated with the spillover signal indicates that an audiencemember associated with the portable metering device was not sufficientlyexposed to the media presentation to indicate consumption of the mediapresentation.
 11. An apparatus to detect spillover to generate mediamonitoring information, comprising: a sensor to receive a first locationsignal and a second location signal substantially simultaneously at aportable metering device, wherein the first location signal is emittedvia a first device located at a first location and includes a firstsignal characteristic associated with the first location, and whereinthe second location signal is emitted via a second device located at asecond location and includes a second signal characteristic associatedwith the second location; and a processor to: select the first locationsignal or the second location signal based on the first and secondsignal characteristics; and generate media monitoring information basedon the selected signal.
 12. An apparatus as defined in claim 11, whereinthe first device is adjacent to a first surface of a wall and the seconddevice is adjacent to a second surface of the wall.
 13. (canceled) 14.An apparatus as defined in claim 11, wherein the first and second signalcharacteristics are associated with at least one of a signal strength, asignal frequency, or a location code.
 15. An apparatus as defined inclaim 11, wherein the processor is to generate the media monitoringinformation by storing an audio code associated with media detected bythe portable metering device while located in one of the first locationor the second location.
 16. (canceled)
 17. (canceled)
 18. An apparatusas defined in claim 11, wherein the processor is further to, whengenerating the media monitoring information based on the selectedsignal, identify the media monitoring information as being associatedwith a spillover signal, the spillover signal being indicative of amedia presentation presented in a second room and detected by theportable metering device located in a first room.
 19. An apparatus asdefined in claim 18, wherein the selected signal is indicative of thefirst room, and wherein the media monitoring information is identifiedas being associated with the spillover signal in response to determiningthat a media delivery device is not located in the first room indicatedby the selected signal.
 20. An apparatus as defined in claim 18, whereinthe media monitoring information being associated with the spilloversignal indicates that an audience member associated with the portablemetering device was not sufficiently exposed to the media presentationto indicate consumption of the media presentation.
 21. A tangiblemachine accessible medium having instructions stored thereon that, whenexecuted, cause a machine to: receive a first location signal and asecond location signal substantially simultaneously at a portablemetering device, wherein the first location signal is emitted via afirst device located at a first location and includes a first signalcharacteristic associated with the first location, and wherein thesecond location signal is emitted via a second device located at asecond location and includes a second signal characteristic associatedwith the second location; select the first location signal or the secondlocation signal based on the first and second signal characteristics;and generate media monitoring information based on the selected signal.22. A machine accessible medium as defined in claim 21, wherein thefirst device is adjacent to a first surface of a wall and the seconddevice is adjacent to a second surface of the wall.
 23. (canceled)
 24. Amachine accessible medium as defined in claim 21, wherein the first andsecond signal characteristics are associated with at least one of asignal strength, a signal frequency, or a location code.
 25. A machineaccessible medium as defined in claim 21 having instructions storedthereon that, when executed, cause the machine to generate the mediamonitoring information by storing an audio code associated with mediadetected by the portable metering device while located in one of thefirst location or the second location.
 26. (canceled)
 27. (canceled) 28.A machine accessible medium as defined in claim 21 having instructionsstored thereon that, when executed, cause the machine to, whengenerating the media monitoring information based on the selectedsignal, identify the media monitoring information as being associatedwith a spillover signal, the spillover signal being indicative of amedia presentation presented in a second room and detected by theportable metering device located in a first room.
 29. A machineaccessible medium as defined in claim 28, wherein the selected signal isindicative of the first room, and wherein the media monitoringinformation is identified as being associated with the spillover signalin response to determining that a media delivery device is not locatedin the first room indicated by the selected signal.
 30. A machineaccessible medium as defined in claim 28, wherein the media monitoringinformation being associated with the spillover signal indicates that anaudience member associated with the portable metering device was notsufficiently exposed to the media presentation to indicate consumptionof the media presentation.